Reverts
5e23a773b4b41163d4a0834e5f1c79305b903795
It seems to cause a crash during msbuild tests:
```
xunit -> Microsoft.Build.Engine.UnitTests...
Stacktrace:
Native stacktrace:
0 mono 0x0017cad4 mono_handle_native_crash + 308
1 mono 0x001e2b03 sigabrt_signal_handler + 147
2 libsystem_platform.dylib 0x920a8deb _sigtramp + 43
3 ??? 0xffffffff 0x0 +
4294967295
4 libsystem_c.dylib 0x940bb27c abort + 155
5 mono 0x0036886d mono_log_write_logfile + 381
6 mono 0x003630d2 structured_log_adapter + 50
7 mono 0x00380d1b monoeg_assertion_message + 107
8 mono 0x0033863d major_scan_object_with_evacuation + 3373
9 mono 0x0033b3d0 drain_gray_stack + 6608
10 mono 0x0032df57 finish_gray_stack + 151
11 mono 0x0032d3c6 major_finish_collection + 118
12 mono 0x00329909 major_do_collection + 169
13 mono 0x003288bd sgen_perform_collection + 605
14 mono 0x0032a90b sgen_gc_collect + 75
15 mono 0x002d5c4d unload_thread_main + 861
16 mono 0x002abb6b start_wrapper + 795
17 libsystem_pthread.dylib 0x9ae6d5fb _pthread_body + 144
18 libsystem_pthread.dylib 0x9ae6d485 _pthread_struct_init + 0
19 libsystem_pthread.dylib 0x9ae72cf2 thread_start + 34
Debug info from gdb:
(lldb) command source -s 0 '/tmp/mono-gdb-commands.2tso9f'
Executing commands in '/tmp/mono-gdb-commands.2tso9f'.
(lldb) process attach --pid 2037
2017-06-02 13:07:23.000 lldb[2093:282f] Metadata.framework [Error]: couldn't get the client port
Process 2037 stopped
* thread #1, name = 'tid_507', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
libsystem_kernel.dylib`__psynch_cvwait:
-> 0x923cc7ca <+10>: jae 0x923cc7da ; <+26>
0x923cc7cc <+12>: calll 0x923cc7d1 ; <+17>
0x923cc7d1 <+17>: popl %edx
0x923cc7d2 <+18>: movl 0xe0b084f(%edx), %edx
Executable module set to "/Users/builder/data/lanes/2716/mono-mac-sdk/external/bockbuild/stage/bin/mono".
Architecture set to: i386-apple-macosx.
(lldb) thread list
Process 2037 stopped
* thread #1: tid = 0x530e96a, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'tid_507', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
thread #2: tid = 0x530e96b, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
thread #3: tid = 0x530e96c, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'SGen worker'
thread #4: tid = 0x530e96d, 0x923c7fb6 libsystem_kernel.dylib`semaphore_wait_trap + 10, name = 'Finalizer'
thread #5: tid = 0x530e96e, 0x923cd992 libsystem_kernel.dylib`kevent64 + 10, queue = 'com.apple.libdispatch-manager'
thread #6: tid = 0x530ea26, 0x923ccace libsystem_kernel.dylib`__select + 10, name = 'tid_5a03'
thread #7: tid = 0x530edf1, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'tid_4007'
thread #8: tid = 0x530edf2, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'Threadpool worker'
thread #9: tid = 0x530edf3, 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10, name = 'Threadpool worker'
thread #10: tid = 0x530edf4, 0x923ccff2 libsystem_kernel.dylib`__wait4 + 10, name = 'Domain unloader'
(lldb) thread backtrace all
* thread #1, name = 'tid_507', queue = 'com.apple.main-thread', stop reason = signal SIGSTOP
* frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
frame #2: 0x9ae71bd9 libsystem_pthread.dylib`pthread_cond_wait$UNIX2003 + 71
frame #3: 0x00361ea9 mono`mono_os_event_wait_multiple + 505
frame #4: 0x00361ca5 mono`mono_os_event_wait_one + 53
frame #5: 0x00376b49 mono`mono_thread_info_wait_one_handle + 41
frame #6: 0x002d51b5 mono`mono_domain_try_unload + 485
frame #7: 0x002d4f6a mono`ves_icall_System_AppDomain_InternalUnload + 90
frame #8: 0x05bf9ee0
frame #9: 0x018ce01d mscorlib.dll.dylib`System_AppDomain_Unload_System_AppDomain + 45
frame #10: 0x05bf9d60
frame #11: 0x05bf9ccc
frame #12: 0x05bf9d04
frame #13: 0x05bf9c90
frame #14: 0x05bf996d
frame #15: 0x02e7d171
frame #16: 0x005c26d4
frame #17: 0x005b6878
frame #18: 0x005b6b7a
frame #19: 0x000c38a8 mono`mono_jit_runtime_invoke + 1592
frame #20: 0x002e43fe mono`do_runtime_invoke + 94
frame #21: 0x002e7de3 mono`do_exec_main_checked + 147
frame #22: 0x002e69a5 mono`mono_runtime_run_main_checked + 69
frame #23: 0x0013b687 mono`mono_jit_exec + 311
frame #24: 0x0013e2b2 mono`mono_main + 10114
frame #25: 0x000b22db mono`main + 2011
frame #26: 0x000b1af5 mono`start + 53
thread #2, name = 'SGen worker'
frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
frame #2: 0x9ae71bd9 libsystem_pthread.dylib`pthread_cond_wait$UNIX2003 + 71
frame #3: 0x0035f0e9 mono`thread_func + 249
frame #4: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
frame #5: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
frame #6: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
thread #3, name = 'SGen worker'
frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
frame #2: 0x9ae71bd9 libsystem_pthread.dylib`pthread_cond_wait$UNIX2003 + 71
frame #3: 0x0035f0e9 mono`thread_func + 249
frame #4: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
frame #5: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
frame #6: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
thread #4, name = 'Finalizer'
frame #0: 0x923c7fb6 libsystem_kernel.dylib`semaphore_wait_trap + 10
frame #1: 0x002dbeb6 mono`finalizer_thread + 278
frame #2: 0x002abb6b mono`start_wrapper + 795
frame #3: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
frame #4: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
frame #5: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
thread #5, queue = 'com.apple.libdispatch-manager'
frame #0: 0x923cd992 libsystem_kernel.dylib`kevent64 + 10
frame #1: 0x91b5c899 libdispatch.dylib`_dispatch_mgr_invoke + 238
frame #2: 0x91b5c532 libdispatch.dylib`_dispatch_mgr_thread + 52
thread #6, name = 'tid_5a03'
frame #0: 0x923ccace libsystem_kernel.dylib`__select + 10
frame #1: 0x0036df29 mono`mono_poll + 409
frame #2: 0x002b482f mono`poll_event_wait + 111
frame #3: 0x002b345f mono`selector_thread + 1439
frame #4: 0x002abb6b mono`start_wrapper + 795
frame #5: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
frame #6: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
frame #7: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
thread #7, name = 'tid_4007'
frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
frame #2: 0x9ae71c25 libsystem_pthread.dylib`pthread_cond_timedwait$UNIX2003 + 71
frame #3: 0x003760f3 mono`mono_thread_info_sleep + 979
frame #4: 0x002b1a86 mono`monitor_thread + 262
frame #5: 0x002abb6b mono`start_wrapper + 795
frame #6: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
frame #7: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
frame #8: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
thread #8, name = 'Threadpool worker'
frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
frame #2: 0x9ae71c25 libsystem_pthread.dylib`pthread_cond_timedwait$UNIX2003 + 71
frame #3: 0x002b12e0 mono`worker_thread + 1024
frame #4: 0x002abb6b mono`start_wrapper + 795
frame #5: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
frame #6: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
frame #7: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
thread #9, name = 'Threadpool worker'
frame #0: 0x923cc7ca libsystem_kernel.dylib`__psynch_cvwait + 10
frame #1: 0x9ae6fd1d libsystem_pthread.dylib`_pthread_cond_wait + 728
frame #2: 0x9ae71c25 libsystem_pthread.dylib`pthread_cond_timedwait$UNIX2003 + 71
frame #3: 0x002b12e0 mono`worker_thread + 1024
frame #4: 0x002abb6b mono`start_wrapper + 795
frame #5: 0x9ae6d5fb libsystem_pthread.dylib`_pthread_body + 144
frame #6: 0x9ae6d485 libsystem_pthread.dylib`_pthread_start + 130
frame #7: 0x9ae72cf2 libsystem_pthread.dylib`thread_start + 34
thread #10, name = 'Domain unloader'
frame #0: 0x923ccff2 libsystem_kernel.dylib`__wait4 + 10
frame #1: 0x940d9ea5 libsystem_c.dylib`waitpid$UNIX2003 + 48
frame #2: 0x0017cba7 mono`mono_handle_native_crash + 519
frame #3: 0x001e2b03 mono`sigabrt_signal_handler + 147
frame #4: 0x920a8deb libsystem_platform.dylib`_sigtramp + 43
(lldb) detach
Process 2037 detached
(lldb) quit
=================================================================
Got a SIGABRT while executing native code. This usually indicates
a fatal error in the mono runtime or one of the native libraries
used by your application.
=================================================================
```