Camera3: don't let dequeueBuffer block indefinitely

The synchronous consumers (e.g. ImageReader) may be very slow when the
clients have computational intensive image processings. When system
load is high, these processing will be even much slower. This could
starve the producer side and then cause dequeue/attach buffer block
indefinitely. If clients intends to close the capture session, right
after a capture request is submitted, the waitUntil drain could be
blocked indefinitely if the capture request dequeue buffer call is
blocked indefinitely, as the request thread will never become idle until
the last dequeue buffer is done and the request is sent.This indefinite
getBuffer() blocking could easily trigger the waitUntilDrained 5s timeout
thus put the camera device into error state although there is nothing
bad happening in the HAL.

Introducing the timeout will avoid such bad situation. When consumer is
slow, there will be no new request being sent to HAL, as there is really
no new buffer available.

Bug:30404840
Change-Id: Ibf08d2745911203bce6f31130800707f36d7f985