Sync web-platform-tests PR 23040 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/23040
Details from upstream follow.

Gyuyoung Kim <gyuyoung@igalia.com> wrote:

[css-grid] Migrate floating-not-effect-on-grid-items.html to WPT

This CL migrates floating-not-effect-on-grid-items.html
from fast/css-grid-layout to
external/wpt/css/css-grid/grid-items with WPT styles,
adding links to the relevant specs, and test description.

Additionally, this test is renamed to
floating-not-effect-on-grid-items-001.html to be align
with existing tests.

Bug: 1063749
Change-Id: I1fe5a1a554ee2e2a15f526c8d1f18b8ba013ce6c
Reviewed-on: https://chromium-review.googlesource.com/2153446
WPT-Export-Revision: 2a3ad43ef70a82a5a6369e1651af9d9a59010b47

CI Results

Ran 13 Firefox configurations based on mozilla-central, and Firefox, Chrome, and Safari on GitHub CI

Total 60 tests

Status Summary

Firefox

OK : 1
PASS: 1[GitHub] 60[Gecko-android-em-7.0-x86_64-debug-geckoview, Gecko-android-em-7.0-x86_64-opt-geckoview, Gecko-linux1804-64-asan-opt, Gecko-linux1804-64-debug, Gecko-linux1804-64-opt, Gecko-linux1804-64-qr-debug, Gecko-linux1804-64-qr-opt, Gecko-windows10-64-debug, Gecko-windows10-64-opt, Gecko-windows10-64-qr-debug, Gecko-windows10-64-qr-opt, Gecko-windows7-32-debug, Gecko-windows7-32-opt]

Chrome

OK : 1
PASS: 1

Safari

OK : 1
PASS: 1

Links

Gecko CI (Treeherder)
GitHub PR Head
GitHub PR Base

https://hg.mozilla.org/mozilla-central/rev/b18034ddbf6f