Ensure that overrides work in presence of package-private methods.

It was possible that methods with the same signature & name of
package-private methods could fail to be correctly overridden causing
surprising behavior and DCHECK failures.

Bug: 32193118
Test: mma test-art-host
Test: ART_TEST_RUN_TEST_NDEBUG=true ART_TEST_RUN_TEST_NO_PREBUILD=true mma test-art-host-run-test-300-package-override
Change-Id: I8f53a830cd8d4210f60e9827e525c779a0696e04