Update trigger.py to take extra arguments The extra_args wildcard doesn't support extra arguments prepended with '--'. By using the unknown args returned by argparse, you can add arbitrary args to the swarming call. Bug: angleproject:3272 Change-Id: I8d4ab1e19ceae80b47cc2331e6e30a4187da863f Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1695921 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>