The test had an additional check to make sure we have coverage on every
platform, but this is unnecessary and requires too much overhead to
maintain a list of good locales for all platforms.

Bug: 941249

Change-Id: I3e6da2ad61453fc385edf5f18101c8cb13ae0503
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/1520989
Commit-Queue: Jonah Ryan-Davis <jonahr@google.com>
Reviewed-by: Geoff Lang <geofflang@chromium.org>
Reviewed-by: Jamie Madill <jmadill@chromium.org>