Add vr flinger test

Add a test to verify basic vr flinger functionality.

Bug: 109670936

Test: Confirmed the test passes successfully on the current master
build. I reverted ag/4197844 locally, which causes surface flinger to
crash when vr flinger is activated. I confirmed the test detected the
crash in surface flinger and reported a fail result, as expected.

Change-Id: Icc4c196d8a216d05c9d7defb4ab8416b900a16d9