This uses the new setting added to depot_tools. The diff
lines of context setting was removed.

Bug: angleproject:4003
Change-Id: I6f7d471d3cce066cd3a6caa200828d09ccfca5ae
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1879577Reviewed-by: Jamie Madill <jmadill@chromium.org>
Commit-Queue: Jamie Madill <jmadill@chromium.org>