GitLab

Adds the ability to replace or remove arguments for tests generated
using generate_buildbot_json.py by specifying a 'replacements' field in
test_suite_exceptions.pyl.

This is useful in cases where a subset of bots have slightly different
args from usual. Previously, this required a duplicate test suite
definition with the updated args. With this change, the same definition
can be used with the differences listed in the exceptions.

Bug: 980631
Change-Id: If3c0c22f2046ce67123ec06dea88a6bf8de9102f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1691266Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Brian Sheedy <bsheedy@chromium.org>
Cr-Commit-Position: refs/heads/master@{#676270}