Add en-XA and ar-XB pseudolocale translation and delete fake-bidi ones

Fake-bidi is completely broken right now, and doesn't actually work, so it's fine to delete it even though the new solution hasn't been enabled yet.

This CL uses parsing, instead of regexes to determine translations, which avoids translating variable names and special tokens.

This is required for go/cros-i18n-testing.

BUG=chromium:1173812
TEST=Ran added unit tests, and verified that chrome builds and translates correctly.

Change-Id: I98ad6907a998662e642e53482d3742dfd39f30d9
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2670479


Commit-Queue: Matt Stark <msta@google.com>
Reviewed-by: Andrew Grieve <agrieve@chromium.org>
Cr-Commit-Position: refs/heads/master@{#850476}