Add unit test for service validation for TvRemoteProvideWatcher.

This checks that validation rules take effect for whitelisting services
that are accepted by the TvRemoteProviderWatcher class.

Bug: 150766750

Test: ran unit tests and it passed via:
  atest services/tests/servicestests/src/com/android/server/tv/TvRemoteProviderWatcherTest.java

Change-Id: I1470a0409c35c6e7b9485f57cf0288527bbf221b