Change test to use a public API method to avoid an implementation
dependency on core-icu4j.

java.lang.reflect.Modifier.classModifiers() is a public static getter
returning a simple static field, just like
android.icu.util.TimeZone.getDefaultTimeZoneType, and we dex2oat with
the implementation dex jars for core-oj where it's implemented.

Test: art/test/testrunner/testrunner.py --target --64 -t 683
Test: art/test/testrunner/testrunner.py --host -t 683
Bug: 202711962
Change-Id: If099f0e8ec9c0057e2b7852e6823e65ecab2112c
2 files changed