Now runs on OpenSolaris i386.

Now runs on OpenSolaris i386.
* src/vm/array.hpp, src/native/jni.cpp: Compile fixes (on OpenSolaris).
* src/vm/jit/i386/arch.h: Added SKIP_REG_DEFS for Solaris build.
Also #undef register symbols on Solaris.
* src/vm/jit/i386/md-abi.h: #undef REG_SP on Solaris.
* src/vm/jit/i386/codegen.c, src/vm/jit/i386/emit.c: Added an include
in order to pick up the register defines from /usr/include/sys.

* src/vm/jit/i386/solaris/md-os.c: Simplified signal handlers
("new-trap-decoding"). Also using UESP instead of ESP.

* src/vm/jit/optimizing/recompiler.cpp: Fixed a bug.
This "sanity" check is not sane in the presence of spurious wakeups.