AudioPolicy: fix test API for focus policy

Remove AudioPolicy.Builder.setIsTestFocusPolicy from system API
  definitions.
Add the required AudioPolicy-related methods to test API, along
  with the test-only AudioPolicy.Builder.setIsTestFocusPolicy
  method

Bug: 130225439
Test: gts-tradefed run gts -m GtsGmscoreHostTestCases -t 'com.google.android.gts.audiopolicy.AudioPolicyHostTest#testFocusPolicy'

Change-Id: I14f52bdc33b7a342f21e664104718b40f4b8a932
7 files changed