Having presubmit called from within the test runner often
requires logic to remove the call again.

After the GN transition it would be better if presubmit is
called by a wrapper script if needed at all. It is run
on upload and on the tryservers anyways.

BUG=chromium:474921

Review-Url: https://codereview.chromium.org/2114653002
Cr-Commit-Position: refs/heads/master@{#37447}