Added WindowManager unit tests to pre-submit

Change-Id: Iaba2de367ab478916610d96b0e3f69d34e0b471c
diff --git a/services/tests/servicestests/Android.mk b/services/tests/servicestests/Android.mk
index 811c0e6..97d8bdd 100644
--- a/services/tests/servicestests/Android.mk
+++ b/services/tests/servicestests/Android.mk
@@ -22,6 +22,7 @@
     guava \
     android-support-test \
     mockito-target-minus-junit4 \
+    platform-test-annotations \
     ShortcutManagerTestUtils
 
 LOCAL_JAVA_LIBRARIES := android.test.runner