Add new profile for monodroid tools (#5699)

Add new profile for monodroid tools (#5699)

* Add new profile for monodroid tools

This allows the XA build to use these instead of needing to build net_4_x.
We build the assemblies against the .NET 4.6 reference assemblies.

* Skip monodroid_tools in verify (aka mcs-compileall)

Exclude it from the test_profiles since running tests makes no sense there.

Also refactor to exclude binary_reference_assemblies as well,
it was already excluded manually in mcs-compileall before.