Tuning of buffer dequeue code to reduce stalls

Queue as many inputs as possible without blocking, then
block on output. Also change the blocking time to 10ms
but allow a little more retries.

Finally, assign a non-zero pts to the image samples to
suppress warnings from MediaCodec about 0 pts.

bug: 78475896

Change-Id: I57c4096a93bc5de0a413968224843a69df667df8