AudioFlinger: Log Record and MMap thread events

Also update track dump for better grouping and consistency.

Test: adb shell dumpsys media.audio_flinger
Bug: 62700410
Bug: 62701585
Change-Id: I3a6e76eac871cb08ff14d45f7d3992a6e7fba045
diff --git a/services/audioflinger/PlaybackTracks.h b/services/audioflinger/PlaybackTracks.h
index af644ed..1c1a989 100644
--- a/services/audioflinger/PlaybackTracks.h
+++ b/services/audioflinger/PlaybackTracks.h
@@ -41,7 +41,7 @@
     virtual status_t    initCheck() const;
 
     static  void        appendDumpHeader(String8& result);
-            void        dump(char* buffer, size_t size, bool active);
+            void        appendDump(String8& result, bool active);
     virtual status_t    start(AudioSystem::sync_event_t event =
                                     AudioSystem::SYNC_EVENT_NONE,
                              audio_session_t triggerSession = AUDIO_SESSION_NONE);