Make ShapeResult::CreateForTabulationCharacters() to have proper GlyphData

This patch changes |ShapeResult::CreateForTabulationCharacters()| to
have proper |character_index| when text direction is RTL as same as
|ShapeResult::CreateForSpaces()|[1].

[1] http://crrev.com/c/2825447: Consider text direction when building
the GlyphData structure

Bug: 1255310
Change-Id: Id91c41c353b34c916eedd8efc3b62bdb413a7a0b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3204614
Commit-Queue: Yoshifumi Inoue <yosin@chromium.org>
Auto-Submit: Yoshifumi Inoue <yosin@chromium.org>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Reviewed-by: Kent Tamura <tkent@chromium.org>
Cr-Commit-Position: refs/heads/main@{#928075}