Use and test patch utilities from system/audio.h

Use `audio_patch_is_valid` function.

Add basic tests for the following functions:
  audio_patch_is_valid
  audio_port_config_has_hw_av_sync
  audio_patches_are_equal

Bug: 63901775
Test: systemaudio_tests
Change-Id: I378ab544e4148fda0dd7b9520d6fd57ff01cb34b
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
index 7154cb2..87cacf8 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
@@ -2834,8 +2834,7 @@
     }
     ALOGV("createAudioPatch() num sources %d num sinks %d", patch->num_sources, patch->num_sinks);
 
-    if (patch->num_sources == 0 || patch->num_sources > AUDIO_PATCH_PORTS_MAX ||
-            patch->num_sinks == 0 || patch->num_sinks > AUDIO_PATCH_PORTS_MAX) {
+    if (!audio_patch_is_valid(patch)) {
         return BAD_VALUE;
     }
     // only one source per audio patch supported for now