Update NetEq Quality Test.

1. move channel number of input file to the base class

2. limit channel number to be 1, since the resampler support only mono at the moment

3. adding a logging function

4. adding more switch to neteq_opus_quality_test

BUG=2692
R=henrik.lundin@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/47239004

Cr-Commit-Position: refs/heads/master@{#9260}
6 files changed