Additional MethodHandle.asType() tests

Added along with fixes in libcore MethodHandle implementation that
allows these tests to pass identically on ART and RI.

NB currently 956-methodhandle has one test failing on RI, but changes
added here work identically there.

Bug: 207844518
Test: art/test.py --host -r
Change-Id: I1687829867d91099117bdd1e8cc5200e20541db0
1 file changed