The WebRTC valgrind wrapper scripts needs to be moved in order to
unlock us from depending on a Chromium checkout.
BUG=webrtc:5006
TBR=ehmaldonado@webrtc.org
NOTRY=True
Review-Url: https://codereview.webrtc.org/2578093002
Cr-Commit-Position: refs/heads/master@{#15662}