[css-pseudo] Set default styles to ::marker

Markers should have the following styles by default:
 - unicode-bidi: isolate
 - font-variant-numeric: tabular-nums

Spec: https://drafts.csswg.org/css-pseudo-4/#marker-pseudo

Bug: 457718

TEST=external/wpt/css/css-pseudo/marker-default-styles.html
TEST=external/wpt/css/css-pseudo/marker-font-variant-numeric-default.html
TEST=external/wpt/css/css-pseudo/marker-font-variant-numeric-normal.html
TEST=external/wpt/css/css-pseudo/marker-unicode-bidi-default.html
TEST=external/wpt/css/css-pseudo/marker-unicode-bidi-normal.html

The unicode-bidi tests fail in legacy because of bug 1012289.
And marker-font-variant-numeric-normal.html fails everywhere because
nested ::marker pseudo-elements are not supported yet.

Change-Id: I80360d0e2bfa78ebca1c10e1064daa17e66e6f22
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1943228
Reviewed-by: Rune Lillesveen <futhark@chromium.org>
Commit-Queue: Oriol Brufau <obrufau@igalia.com>
Cr-Commit-Position: refs/heads/master@{#720875}
22 files changed