This is a reland of 1cb4c9a70836c34cc0d5260902f71d3e8a2f67ec

Rebaselined a few tests for mac 10.14 and 10.15.

Original change's description:
> New TextBreakIterator's default behavior breaks after space run
>
> Before this change, we were considering breaking opportunities before
> space runs. This approach allowed us to avoid re-shaping in many cases,
> which has an important advantage in terms of performance.
>
> However, the Unicode spec (UAX#14) state that breaking before a space
> character is not allowed [1], so we had to implement this logic after
> our TextBreakIterator had already determined the best breaking
> opportunity. This approach has been working fine so far for regular
> spaces (white-space, tabs, ...), but it doesn't work correctly for
> other BA [2] class characters; in the CSS Text specification, these are
> known as "other space separators" [3].
>
> In order to implement the correct behavior for any kind of space, we
> would need to change our TextBreakIterator implementation so that
> matches the Unicode rules, considering breaking opportunity after
> space runs. This change should also consider the performance impact
> of the extra re-shaping operations required to deal with trailing
> spaces.
>
> In order to prevent performance regressions, we'll store the position
> of the 'end of non-hangable run', which will be used in case of items
> with styles dictating rules to collapse trailing spaces.
>
> [1] https://unicode-org.atlassian.net/browse/ICU-20843
> [2] https://www.unicode.org/reports/tr14/tr14-39.html#BA
> [3] https://drafts.csswg.org/css-text-3/#other-space-separators
>
> Change-Id: Ie4a3890c75a3faff1a0155d4a40bcaa85bc6ac06
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2047943
> Commit-Queue: Javier Fernandez <jfernandez@igalia.com>
> Reviewed-by: Koji Ishii <kojii@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#806928}

Change-Id: I9b5204f0b2e49367ab7d7a2107900763844fd2bb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2412307
Commit-Queue: Javier Fernandez <jfernandez@igalia.com>
Reviewed-by: Koji Ishii <kojii@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807457}