Use prebuilt android.test. stubs jars for app builds

(cherry picked from commit e144602d9c94d46b2da11d70f526d747b5e05750)

Bug: 30188076
Test: tapas Launcher3
Change-Id: I48864d48098cfa02e15a6eaf8e4d6b53afc5b56c
Merged-In: If632c39c9d98d89d597d410ebc7973903c9fa91e
diff --git a/test-runner/Android.mk b/test-runner/Android.mk
index 37cd084..67f1354 100644
--- a/test-runner/Android.mk
+++ b/test-runner/Android.mk
@@ -16,6 +16,9 @@
 
 LOCAL_PATH:= $(call my-dir)
 
+# For unbundled build we'll use the prebuilt jar from prebuilts/sdk.
+ifeq (,$(TARGET_BUILD_APPS)$(filter true,$(TARGET_BUILD_PDK)))
+
 # Generate the stub source files for android.test.runner.stubs
 # ============================================================
 include $(CLEAR_VARS)
@@ -111,3 +114,5 @@
 	$(hide) $(ACP) $(ANDROID_TEST_RUNNER_OUTPUT_API_FILE) $(ANDROID_TEST_RUNNER_API_FILE)
 	@echo Copying removed.txt
 	$(hide) $(ACP) $(ANDROID_TEST_RUNNER_OUTPUT_REMOVED_API_FILE) $(ANDROID_TEST_RUNNER_REMOVED_API_FILE)
+
+endif  # not TARGET_BUILD_APPS not TARGET_BUILD_PDK=true