Sync web-platform-tests PR 21654 into mozilla-central (this bug is closed when the sync is complete).

PR: https://github.com/web-platform-tests/wpt/pull/21654
Details from upstream follow.

Fredrik Söderquist <fs@opera.com> wrote:

Reland "Move SMIL events tests to WPT"

Now with \<script> elements in the HTML namespace. Because reasons.

Change-Id: Ia3eba0f7856f265ed6fa601272a2d7c577b07c1c
Reviewed-on: https://chromium-review.googlesource.com/2043450
WPT-Export-Revision: 879de972b73e5e9efc2c4472abd2dc5de27d4eab

CI Results

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

Total 55 tests

Status Summary

Firefox

OK : 12
PASS : 12[GitHub] 55[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 : 12
PASS : 12

Safari

OK : 7
PASS : 6
FAIL : 1
TIMEOUT: 10

Links

Gecko CI (Treeherder)
GitHub PR Head
GitHub PR Base

https://hg.mozilla.org/mozilla-central/rev/0bd1f951029b