Comment out code accidentally left in the bitstream_debug patch

In https://aomedia-review.googlesource.com/#/c/5864/ , some
code to stop the decoder at a preselected point was left enabled.
This code should only be uncommented when debugging, so comment
it out by default.

Change-Id: Ie168e8a1588ba92971e3ff1a056f597a7dfca136
1 file changed