Modify NetEqQualityTest

- Take input sample rate as parameter - provides resampling when needed.
- Add support for wav output.

BUG=2692
R=minyue@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/49699004

Cr-Commit-Position: refs/heads/master@{#9158}
8 files changed