ART: Add ClassLoadCallback

Add callback for class-load and class-prepare events. Move Dbg
over. Add tests.

Bug: 31684920
Test: m test-art-host-gtest-runtime_callbacks_test
Test: art/tools/run-jdwp-tests.sh --mode=host
Change-Id: I871f6b3c54448fd6ece8d9a7571b2042be50d525
diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index 5bdfbc7..f708e26 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -107,6 +107,7 @@
 ART_GTEST_reflection_test_DEX_DEPS := Main NonStaticLeafMethods StaticLeafMethods
 ART_GTEST_profile_assistant_test_DEX_DEPS := ProfileTestMultiDex
 ART_GTEST_profile_compilation_info_test_DEX_DEPS := ProfileTestMultiDex
+ART_GTEST_runtime_callbacks_test_DEX_DEPS := XandY
 ART_GTEST_stub_test_DEX_DEPS := AllFields
 ART_GTEST_transaction_test_DEX_DEPS := Transaction
 ART_GTEST_type_lookup_table_test_DEX_DEPS := Lookup