DO NOT MERGE: audio: Skip tests if audio HAL service lacks "primary" device

Non-default audio service (e.g. MSD) is allowed not to have
a "primary" device. In this case tests that require it can be
skipped.

This is Android P specific version of the change.

Bug: 139321356
Bug: 141433379
Test: vts-tradefed run commandAndExit vts -m VtsHalAudioV4_0Target
      on a device with "msd" audio HAL module

Change-Id: I3b999664130013294cebd26976a1b18354926a5e