Makes it possible to robo-test Settings app fragments.

This adds bunch of shadow/placeholder classes and logic to handle
references to Android internal resources or newly added classes/methods
that Robolectric hasn't yet picked up.

Developers can follow ManageApplicationsTest example to use the shadow
classes and the utility method to start ther fragment in their
robolectric tests.

Bug: 33431346
Test: This is a test improvement CL. RunSettingsRoboTests still passes.
Change-Id: I943ab871631cb8c368d9f9db481c00558c5c4d1f

tests/robotests/src/com/android/internal/app/LocalePickerWithRegion.java

@@ -0,0 +1,11 @@
+package com.android.internal.app;
+
+/**
+ * A placeholder class to prevent ClassNotFound exceptions caused by lack of visibility.
+ */
+public class LocalePickerWithRegion {
+
+    public interface LocaleSelectedListener {
+        void onLocaleSelected(LocaleStore.LocaleInfo locale);
+    }
+}