Add new tests
When looking for base implementation of generic MVAR methods use non-inflated parameter types. Fixes #15523
Tests update
[linker]: Also reference all type-references for LinkAction.Link and Save.
[runtime] Promote the reference queue API to the public.
[runtime] Improve the docs on reference queues a bit.
Add LLDB support to mono_gdb_render_native_backtraces () on POSIX.
Fixed a test issue where net45 methods were used in net40 profile
[runtime]Add a wrapper around signal handlers to ease porting work.
Correct VFP detection in mono-hwcap-arm.

This is supposed to be the value 64, not 100.
Enable GCC atomics on sparc32/64.
Remove dead s390(x) code from mono-membar.h.
Merge pull request #790 from akoeplinger/fixtests

Fixed a test issue where net45 methods were used in net40 profile
Define WIN32_LEAN_AND_MEAN before including windows.h.
Don't assert in Interlocked.Add () icalls on 64-bit systems.

The checks here were wrong in the first place; they should have
checked for MONO_ARCH_HAVE_ATOMIC_ADD rather than SIZEOF_VOID_P.
But regardless, these methods need to work when invoked via
reflection, which they wouldn't previously.
Ignore .dirstamp files.
Add a .gitignore file to support/minizip/ to ignore *.la *.lo files.
Silence some noisy warnings in mono/tests/.
Enum subtraction quirk needs to work with numeric constants only. Fixes #15520
Update lower/upper type inference fixing to match the latest C# standard. Fixes #15505