Map U+0909 and U+0993 to 3 when checking for confusables

U+0909 (उ) and U+0993 (ও) look similar to the number 3. Thic cl adds
these two characters to the mapping to 3 when determining whether to
fall back to punycode when displaying URLs.

Bug: 895885
Change-Id: I233127570c8e34e791ef5663c1ece9207d6c7bda
Reviewed-on: https://chromium-review.googlesource.com/c/1287031
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#600544}