Fix underlay testing issue on video power measurement

It fails on certain video sites, for example:
http://crosvideo.appspot.com

Also, this CL adds an option --bypass-ipg so that we can
debug testing harness where Intel Power Gadget is not
supported.

BUG=868561
TEST=manual, GPU bots
R=magchen@chromium.org

Change-Id: I0e8a2882dab4a1fcf6d5989e65dc36d57cad165a
Reviewed-on: https://chromium-review.googlesource.com/c/1471295
Commit-Queue: Zhenyao Mo <zmo@chromium.org>
Reviewed-by: Sunny Sachanandani <sunnyps@chromium.org>
Reviewed-by: Maggie Chen <magchen@chromium.org>
Cr-Commit-Position: refs/heads/master@{#632466}
2 files changed