Re-enable all MethodHandleCombinersTest tests

Compiler fix in https://r.android.com/2238847 means these tests
should no longer fail. Issue no longer repros in manual testing.

Fix: 241199625
Test: art/tools/run-libcore-tests.sh --mode=device --variant=X64 \
        libcore.java.lang.invoke.MethodHandleCombinersTest
Change-Id: Ie272472a6c8086d467003e1a145e8239eaa70b3e