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

Implement DedicatedWorkerGlobalScope.close

<!-- Please describe your changes on the following line: -->
Implement DedicatedWorkerGlobalScope.close().
---
<!-- Thank you for contributing to Servo! Please replace each `[ ]` by `[X]` when the step is complete, and replace `__` with appropriate data: -->
- [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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tests/wpt/metadata/workers/WorkerGlobalScope_close.htm.ini

@@ -1,5 +0,0 @@
-[WorkerGlobalScope_close.htm]
-  type: testharness
-  [ WorkerGlobalScope close(): clear events queue ]
-    expected: FAIL
-

tests/wpt/metadata/workers/interfaces.worker.js.ini

@@ -21,9 +21,6 @@
   [DedicatedWorkerGlobalScope interface: attribute onmessage]
     expected: FAIL
 
-  [WorkerGlobalScope interface: self must inherit property "close" with the proper type (2)]
-    expected: FAIL
-
   [WorkerGlobalScope interface: self must inherit property "onerror" with the proper type (3)]
     expected: FAIL
 

tests/wpt/metadata/workers/interfaces/WorkerGlobalScope/close/sending-messages.html.ini

@@ -1,6 +0,0 @@
-[sending-messages.html]
-  type: testharness
-  expected: TIMEOUT
-  [close() and sending messages]
-    expected: TIMEOUT
-