Auto merge of #14648 - cynicaldevil:xmlhttpreq-send, r=KiChjang

Implemented XMLHttpRequest.send(Document)

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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 #9490 .

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r? @KiChjang

`XMLHttpRequest/send-entity-body-document.htm` is not working atm, I get this output:
```
$ ./mach test-wpt tests/wpt/web-platform-tests/XMLHttpRequest/send-entity-body-document.htm
Running 1 tests in web-platform-tests

Ran 1 tests finished in 0.0 seconds.
  • 1 ran as expected. 1 tests skipped.
```
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components/script/dom/webidls/XMLHttpRequest.webidl

@@ -53,7 +53,7 @@ interface XMLHttpRequest : XMLHttpRequestEventTarget {
            attribute boolean withCredentials;
   readonly attribute XMLHttpRequestUpload upload;
   [Throws]
-  void send(optional /*Document or*/ BodyInit? data = null);
+  void send(optional (Document or BodyInit)? data = null);
   void abort();
 
   // response