[swarming] Add additional tests covering Unicode.
[swarming] Add additional tests covering Unicode.

Change-Id: Ib69961d35ab30fad6f5197275369fb7863c63d75
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-py/+/2741881
Reviewed-by: Junji Watanabe <aaef61ef98ffea505db831f310be2a0eb8492537@google.com>
Reviewed-by: Takuto Ikuta <71927f930fca81015e0f496c65cd126ab1a692e3@chromium.org>
Commit-Queue: Michal Kiedys <472a1e6216c9a44ed7bded64510d0626a6b6ca20@google.com>

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