Auto merge of #14630 - bd339:iss14064, r=KiChjang

Use MediaQueryListEvent for media query list change events

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- Implements MediaQueryListEvent interface
- Makes MediaQueryList change events conform to the [spec](https://drafts.csswg.org/cssom-view/#evaluate-media-queries-and-report-changes)
- Updates matchMedia.html test to verify that the new event type is used

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- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix #14064

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- [ ] These changes do not require tests because _____

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components/script/dom/webidls/MediaQueryListEvent.webidl

@@ -0,0 +1,15 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+// https://drafts.csswg.org/cssom-view/#dom-mediaquerylistevent-mediaquerylistevent
+[Constructor(DOMString type, optional MediaQueryListEventInit eventInitDict), Exposed=(Window)]
+interface MediaQueryListEvent : Event {
+  readonly attribute DOMString media;
+  readonly attribute boolean matches;
+};
+
+dictionary MediaQueryListEventInit : EventInit {
+  DOMString media = "";
+  boolean matches = false;
+};