Fix RUNTIME_TARGET_GTEST_MAKE_TARGETS

This was including only the <filename>, while Soong test_per_src tests
are exposed to make as <name>_<filename>. So deconstruct the path, which
uses .../<name>/<filename>, instead of just taking the basename.

This has been causing warnings on some internal branch builds, about how
we were asking for these modules, but that they didn't exist. This
change removes those warnings.

Test: Check warnings on internal branches
Change-Id: I4b8559961f51cc32f2fac0bf6fb15ee34ba72bdd
diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index be27869..7ca7409 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -705,7 +705,7 @@
 
 # Used outside the art project to get a list of the current tests
 RUNTIME_TARGET_GTEST_MAKE_TARGETS :=
-$(foreach file, $(ART_TARGET_GTEST_FILES), $(eval RUNTIME_TARGET_GTEST_MAKE_TARGETS += $$(notdir $$(basename $$(file)))))
+$(foreach file, $(ART_TARGET_GTEST_FILES), $(eval RUNTIME_TARGET_GTEST_MAKE_TARGETS += $$(notdir $$(patsubst %/,%,$$(dir $$(file))))_$$(notdir $$(basename $$(file)))))
 COMPILER_TARGET_GTEST_MAKE_TARGETS :=
 
 # Define all the combinations of host/target, valgrind and suffix such as: