audiovideo_Microphone - Fix several minor issues within the test

1. The named temp file should be deleted automatically when it closed.

2. Check both sides of the file size.

3. The 'grep' returns non zero code when it fail to match the pattern.
   This is not what we want in the test

4. Reduce the recording duratin to speedup the test.

BUG=None
TEST=Run the test on parrot

Change-Id: I9323d727319ca077f7d09b24c6d3ae16bd7f4bb5
Reviewed-on: https://chromium-review.googlesource.com/178519
Reviewed-by: Hsinyu Chao <hychao@chromium.org>
Commit-Queue: Owen Lin <owenlin@chromium.org>
Tested-by: Owen Lin <owenlin@chromium.org>
1 file changed