Disable flaky test.java.lang.invoke.MethodTypeTest tests

vogar may not properly support @BeforeMethod and @AfterMethod
annotations so testGeneric() and testMakeGeneric() are flaky on
art-buildbot.

This CL disables these tests before vogar gets a fix which is tracked by
http://b/231292654.

Bug: 231292654
Bug: 231283845
Test: art/tools/run-libcore-tests.sh --mode=host -- \
      test.java.lang.invoke.MethodTypeTest
Change-Id: I03efc5591417825a4afabc525f988fb0c36d8187
1 file changed