Make it possible to isolate isac_fix_test.

Successful swarming run:
https://chromium-swarm.appspot.com/task?id=38769e8dd5d3e110&refresh=10&show_raw=1

BUG=chromium:755660
NOTRY=True

Review-Url: https://codereview.webrtc.org/3009203002
Cr-Original-Commit-Position: refs/heads/master@{#19738}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: 25586cefddcc4b38a5260ef1c6b8cc72b9c1893e
1 file changed