Add onBootPhase call to tests that use AudioDevice

Audio Device now checks for the screen on status when logical address
allocation completes. Any test that depends on this feature will have to
make sure that the onBootPhase is called so that mDisplayManager is not
null in isScreenOff() of HdmiControlService

Bug: 194790930
Test: atest com.android.server.hdmi
Change-Id: I7137f4e5d9978a4bc997a0ab6b03621ec3f2bb25