Runtime resource overlay, iteration 2, test cases

Add automated test cases for runtime resource overlay, iteration 2.

The test cases are a mixture of 'adb shell' commands and regular
instrumentation tests. The device is rebooted between tests to setup
different overlay scenarios for framework-res.apk.

To verify Runtime resoure overlay, iteration 2, run
    $ frameworks/base/core/tests/overlaytests/testrunner.py

For a list of supported options, run
    $ frameworks/base/core/tests/overlaytests/testrunner.py --help

Change-Id: I692aa1a7ad073efd116b24f9ec7f197dfd65dfef