The change in https://chromium-review.googlesource.com/438330
wasn't sufficient to fix the memcheck bot.
This CL also removes the need for other tools than memcheck, since
those are no longer supported anyway.

BUG=libyuv:676
NOTRY=True

Change-Id: I23b7ebd0c2c9008cd2b0b4369edaef99a6687f7a
Reviewed-on: https://chromium-review.googlesource.com/438447Reviewed-by: Henrik Kjellander <kjellander@chromium.org>
Commit-Queue: Henrik Kjellander <kjellander@chromium.org>