Add android.test.base/stubs dependency

In preparation for the removal of the non-junit classes in the
android.test.base library from the android.jar this adds a dependency
on android.test.base/stubs to ensure this code will continue to
compile.

The following change descriptions were generated automatically and so
may be a little repetitive. They are provided to give the reviewer
enough information to check the comments match what has actually been
changed and check the reasoning behind the changes.

* tests/Android.mk
    Added 'android.test.base.stubs' to LOCAL_JAVA_LIBRARIES because
    LatinIMETests's will need them in order to compile once its classes
    are removed from the current SDK on which it currently depends.

Bug: 30188076
Test: make dist
Change-Id: I9f2244d4b5711620dc02dd24dc407807d726480e

tests/Android.mk

@@ -28,7 +28,11 @@ LOCAL_STATIC_JAVA_LIBRARIES := \
     android-support-test \
     mockito-target-minus-junit4
 
-LOCAL_JAVA_LIBRARIES := android.test.mock.stubs android.test.runner.stubs
+LOCAL_JAVA_LIBRARIES := \
+    android.test.mock.stubs \
+    android.test.runner.stubs \
+    android.test.base.stubs \
+
 
 # Include all test java files.
 LOCAL_SRC_FILES := $(call all-java-files-under, src)