Add support for ANDROID_RUNTIME_ROOT variable

This commit introduces the ANDROID_RUNTIME_ROOT environment
variable in preparation for its use within the runtime module.

As a module, ART must no longer use the Android-wide
ANDROID_ROOT environment variable as the base of default
paths for module content. ANDROID_RUNTIME_ROOT will take over
the responsibility. It remains a variable to unify host
and device treatment.

Some test methods (SetUpAndroidData, TearDownAndroidData
SetUpAndroidRoot) have been renamed to clarify their purpose.

Bug: 119935277
Test: build / treehugger
Change-Id: I7c7de52911cbfa56cef90270425ed369176c4767
diff --git a/build/Android.gtest.mk b/build/Android.gtest.mk
index e610bb1..9a5e26b 100644
--- a/build/Android.gtest.mk
+++ b/build/Android.gtest.mk
@@ -422,6 +422,8 @@
   ART_GTEST_TARGET_ANDROID_ROOT := $(ART_TEST_ANDROID_ROOT)
 endif
 
+ART_GTEST_TARGET_ANDROID_RUNTIME_ROOT := '/apex/com.android.runtime'
+
 # Define a make rule for a target device gtest.
 # $(1): gtest name - the name of the test we're building such as leb128_test.
 # $(2): path relative to $OUT to the test binary
@@ -472,7 +474,9 @@
 	$(hide) $(ADB) shell $$(PRIVATE_MAYBE_CHROOT_COMMAND) chmod 755 $$(PRIVATE_TARGET_EXE)
 	$(hide) $$(call ART_TEST_SKIP,$$@) && \
 	  ($(ADB) shell "$$(PRIVATE_MAYBE_CHROOT_COMMAND) env $(GCOV_ENV) LD_LIBRARY_PATH=$(4) \
-	       ANDROID_ROOT=$(ART_GTEST_TARGET_ANDROID_ROOT) $$(PRIVATE_TARGET_EXE) \
+	       ANDROID_ROOT=$(ART_GTEST_TARGET_ANDROID_ROOT) \
+	       ANDROID_RUNTIME_ROOT=$(ART_GTEST_TARGET_ANDROID_RUNTIME_ROOT) \
+	       $$(PRIVATE_TARGET_EXE) \
 	     && touch $$(PRIVATE_GTEST_WITNESS)" \
 	   && ($(ADB) pull $$(PRIVATE_GTEST_WITNESS) /tmp/ && $$(call ART_TEST_PASSED,$$@)) \
 	   || $$(call ART_TEST_FAILED,$$@))
@@ -717,6 +721,7 @@
 ART_TEST_TARGET_GTEST$(2ND_ART_PHONY_TEST_TARGET_SUFFIX)_RULES :=
 ART_TEST_TARGET_GTEST_RULES :=
 ART_GTEST_TARGET_ANDROID_ROOT :=
+ART_GTEST_TARGET_ANDROID_RUNTIME_ROOT :=
 ART_GTEST_class_linker_test_DEX_DEPS :=
 ART_GTEST_class_table_test_DEX_DEPS :=
 ART_GTEST_compiler_driver_test_DEX_DEPS :=