Add explicitly the runner for CtsAppTestCases

apk has several instrumentation, explicitly set the runner.

Test: make cts
Bug: 117322829
Change-Id: I265a802142c4e8431c4af383d172f70b2b598342
Merged-In: Iea84b8c6cee8b1e698c6d4119b7b003b0337afcb
(cherry picked from commit 99b8f94b2b411eaf990d5a6352bd68aea4858c3f)
diff --git a/tests/app/AndroidTest.xml b/tests/app/AndroidTest.xml
index fbc5c38..69505c3 100644
--- a/tests/app/AndroidTest.xml
+++ b/tests/app/AndroidTest.xml
@@ -27,6 +27,7 @@
         <option name="test-file-name" value="CtsCantSaveState2.apk" />
     </target_preparer>
     <test class="com.android.tradefed.testtype.AndroidJUnitTest" >
+        <option name="runner" value="android.support.test.runner.AndroidJUnitRunner" />
         <option name="package" value="android.app.cts" />
         <option name="runtime-hint" value="6m38s" />
         <option name="hidden-api-checks" value="false"/>