audio_processing/tests: Adds a flag to unpack input data to text file

For quick and easy aecdump verifiation storing data as text speeds up the issue tracking process, since anyone can simply view values like mic volume.

BUG=4609
TESTED=verified unpacking an aecdump with flag --txt stores that data in text files
R=kwiberg@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/50849004

Cr-Commit-Position: refs/heads/master@{#9142}
1 file changed