Add support for "data" attribute to cc_test_on_android rule.

Previously, data was being passed on only to the cc_binary rule,
and not to the android_test, which wasn't sufficient.

This also required adding READ_EXTERNAL_STORAGE permission for tests built with
cc_test_on_android, since that permission is needed for accessing test runfiles.

PiperOrigin-RevId: 256110232

Author: Googler

testing/templates/ActivityManifest.xml.tmpl

@@ -4,6 +4,7 @@
     android:versionCode="1"
     android:versionName="1.0.0">
   <uses-sdk android:targetSdkVersion="25" android:minSdkVersion="14" />
+  <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
   <application
       android:allowBackup="false"
       android:label=".$activity_name">