Bug 1731297 [wpt PR 30707] - [@layer] User layer order to resolve @font-face family...

Bug 1731297 [wpt PR 30707] - [@layer] User layer order to resolve @font-face family name conflicts, a=testonly

Automatic update from web-platform-tests
[@layer] User layer order to resolve @font-face family name conflicts

@font-face rules and other name-defining at rules are different that,
rules with the same font-family name do not completely override each
other, but have different priorities in font fallback.

Therefore, this patch modifies CSSSegmentedFontFace to store CSS-
connected font faces in the cascade layer order, so that font faces in
a higher layer will be attempted first in font fallback.

Bug: 1096765
Change-Id: Iccd84b0fd48f1e13eb536a48eabc7f22ccd32149
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/3159011
Commit-Queue: Xiaocheng Hu <xiaochengh@chromium.org>
Reviewed-by: Anders Hartvoll Ruud <andruud@chromium.org>
Cr-Commit-Position: refs/heads/main@{#921814}

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wpt-commits: fe202178b19272c12e2e113c66eecbc1384c8cc5
wpt-pr: 30707