Split image_test and oatdump_test.

With sufficient -j, splitting the oatdump_test makes gtests
finish faster, splitting image_test makes valgring tests
finish faster.

make -j 48 valgrind-test-art-host-gtest
  - before: #### make completed successfully (05:20:16 (hh:mm:ss)) ####
  - after: #### make completed successfully (03:05:43 (hh:mm:ss)) ####
Note that the new image_*test variants are still running
long after the rest of the tests is finished. Further
splitting may still be beneficial for host tests. Target
tests with lower -j parameter do not benefit that much.

Test: make -j 48 valgrind-test-art-host-gtest
Bug: 36849303
Change-Id: I2b887e6b3266f9d3efd7b4d71dde0fcf012829d2
diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index 11af1c0..c4374f7 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -227,6 +227,8 @@
   $(TARGET_CORE_IMAGE_DEFAULT_64) \
   $(TARGET_CORE_IMAGE_DEFAULT_32) \
   oatdump
+ART_GTEST_oatdump_image_test_HOST_DEPS := $(ART_GTEST_oatdump_test_HOST_DEPS)
+ART_GTEST_oatdump_image_test_TARGET_DEPS := $(ART_GTEST_oatdump_test_TARGET_DEPS)
 
 # Profile assistant tests requires profman utility.
 ART_GTEST_profile_assistant_test_HOST_DEPS := \