Auto merge of #12501 - mephisto41:worker-close-impl, r=KiChjang

Implement DedicatedWorkerGlobalScope.close

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Implement DedicatedWorkerGlobalScope.close().
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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 #12466 (github issue number if applicable).

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- [X] There are tests for these changes

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components/script/dom/webidls/DedicatedWorkerGlobalScope.webidl

@@ -8,4 +8,6 @@
   [Throws]
   void postMessage(any message/*, optional sequence<Transferable> transfer*/);
            attribute EventHandler onmessage;
+
+  void close();
 };