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

Bug: 30188076
Test: make dist
Change-Id: Ie5aded464a8ae6c6ea68d88079ce06b3deea8903
diff --git a/tests/robolectric/Android.mk b/tests/robolectric/Android.mk
index f9c6bf2..4b2c618 100644
--- a/tests/robolectric/Android.mk
+++ b/tests/robolectric/Android.mk
@@ -20,7 +20,8 @@
 LOCAL_JAVA_LIBRARIES := \
     junit \
     platform-robolectric-3.1.1-prebuilt \
-    sdk_vcurrent
+    sdk_vcurrent \
+    android.test.base
 
 LOCAL_STATIC_JAVA_LIBRARIES := \
     android-support-v7-preference \