MPEG4Writer: Better logging in DumpTimeStamps()

Current Log messages when recording stops before receiving first frame.
E MPEG4Writer: Dumping Video track's last 10 frames timestamp and frame type
E MPEG4Writer:
E MPEG4Writer:

That is split between two prints.

After this change, it would be a one print statement with all data.
E/MPEG4Writer: Dumping Video track's last 10 frames' timestamps(pts, dts) and frame type :
               (369851us, 369851us Non-Key frame)
	       (403171us, 403171us Non-Key frame)

E/MPEG4Writer: 0 frames to dump in Audio track

Bug: 129554199

Test: Checked that expected log messages were present when recording
      as mentioned in the description above for both cases.

Change-Id: If6c3b96f30b6ebe9e0cca479c7258b5fe3c5dec8