Make sure latest toolchains are build in non vanilla testing.

Our non-vanilla testing builds with latest compiler but it
was not using --latest_toolchain argument for cbuildbot.
Also, did some minor cleanup.

BUG=None
TEST=None (will let it test in the nightly testing)

Change-Id: I7316fcd8b9548f7038b110bdf6cd4f60714f41d2
Reviewed-on: https://chrome-internal-review.googlesource.com/214363
Commit-Queue: Luis Lozano <llozano@chromium.org>
Tested-by: Luis Lozano <llozano@chromium.org>
Reviewed-by: Caroline Tice <cmtice@google.com>
3 files changed