Refreshed UX for Audio Formats Setting [Backend]

This CL modifies getSurroundSound(reported=true) to always return formats
supported by device irrespective of mode.
This also adds unit tests to verify the APIs getSurroundSound and
setSurroundFormatEnabled.

Bug:171785330

Test: atest audiopolicy_tests
Test: Tested manually

Change-Id: Id309cc864fd380d7600c19e1839a63dd5756879f
diff --git a/services/audiopolicy/tests/resources/Android.bp b/services/audiopolicy/tests/resources/Android.bp
index 4f50dad..2f6e925 100644
--- a/services/audiopolicy/tests/resources/Android.bp
+++ b/services/audiopolicy/tests/resources/Android.bp
@@ -5,5 +5,6 @@
         "test_audio_policy_primary_only_configuration.xml",
         "test_invalid_audio_policy_configuration.xml",
         "test_tv_apm_configuration.xml",
+        "test_settop_box_surround_configuration.xml",
     ],
 }