[swarming] accept unknown args to propagate in local_smoke_test.py
[swarming] accept unknown args to propagate in local_smoke_test.py

This fixes the following error.

❯ ./local_smoke_test.py Test.test_io_timeout
usage: local_smoke_test.py [-h] [-v] [--leak] [--bot_python BOT_PYTHON]
local_smoke_test.py: error: unrecognized arguments: Test.test_io_timeout

Bug: 1104068
Change-Id: I94d0740937f1890915d6b9ce16418496238332c2
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/2299159
Auto-Submit: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>
Reviewed-by: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Commit-Queue: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Commit-Queue: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>

luci/luci-py,luci/luci-py,luci/luci-py,luci/luci-py