audio_processing/tests: Adds a flag to unpack input data to text file
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-Original-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#9142}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 40a6d593d26cb87421ab40c3a7ec023f6501721c

Alkalyne/webrtctrunk,jchavanton/webrtc,Alkalyne/webrtctrunk,krieger-od/webrtc,jchavanton/webrtc,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,krieger-od/webrtc,aleonliao/webrtc-trunk,jchavanton/webrtc,Alkalyne/webrtctrunk,Alkalyne/webrtctrunk,sippet/webrtc,aleonliao/webrtc-trunk,sippet/webrtc,sippet/webrtc,krieger-od/webrtc,sippet/webrtc,jchavanton/webrtc,Alkalyne/webrtctrunk,jchavanton/webrtc,Alkalyne/webrtctrunk,krieger-od/webrtc,krieger-od/webrtc,sippet/webrtc,aleonliao/webrtc-trunk,jchavanton/webrtc,krieger-od/webrtc,aleonliao/webrtc-trunk,sippet/webrtc,jchavanton/webrtc,aleonliao/webrtc-trunk,aleonliao/webrtc-trunk