[coop][interp] two failing tests with checked-build=gc

[lewurm]

Build runtime with:

$ ./autogen.sh --enable-checked-build=gc --disable-hybrid-suspend --enable-cooperative-suspend

and run tests with

$ MONO_CHECK_MODE=gc make -C mono/tests testinterp -j18

safehandle.2.exe
=============== safehandle.2.exe.stdout ===============
Good: got exception requried
test_0_safehandle_ref: pass
GOOD: got exception required: System.MissingMethodException: paramterless constructor required
  at (wrapper managed-to-native) Tests.mono_safe_handle_return_2()
  at Tests.test_0_safehandle_return_noctor () <0x7fbfe280cda0 + 0x00004> in <e7fbfcff6f6d4f6e855e71351faff66f>:0
GOOD: got exception required
Got the following handle: 268496909
codigo eadcafe
class.c:3363: Expected GC Unsafe mode but was in STATE_BLOCKING state

pinvoke2.exe
=============== pinvoke2.exe.stdout ===============
object.c:7075: Expected GC Unsafe mode but was in STATE_BLOCKING state

[marek-safar]

/cc @SamMonoRT @BrzVlad