Update some run tests to work when either D8 or R8 is used on libcore.
Test: atest art-run-test-100-reflect2 art-run-test-910-methods
with and without using R8 on libcore (CLs with hashtag
"noop-r8-on-corelibs")
Bug: 317513933
Flag: TEST_ONLY
Change-Id: I6f451cc35f9a80a94015c105bbd6907b6b772ef5