Auto merge of #15455 - charlesvdv:xhr-process-event, r=KiChjang

Implement XHR progress event changes

<!-- Please describe your changes on the following line: -->

This PR implements change in the specs in XHR.

Unfortunatelly, @jdm the test are not passing. It looks like the fetch module send more bytes that we should according the ```Content-Length```. This [lines](https://github.com/servo/servo/blob/master/tests/wpt/web-platform-tests/XMLHttpRequest/progress-events-response-data-gzip.htm#L70) make the test fail.

---
<!-- 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 #13276  (github issue number if applicable).

<!-- Either: -->
- [X] There are tests for these changes OR
- [ ] These changes do not require tests because _____

<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->

<!-- Reviewable:start -->
---
This change is [<img src="https://reviewable.io/review_button.svg" height="34" align="absmiddle" alt="Reviewable"/>](https://reviewable.io/reviews/servo/servo/15455)
<!-- Reviewable:end -->

tests/wpt/metadata/XMLHttpRequest/progress-events-response-data-gzip.htm.ini

@@ -1,5 +0,0 @@
-[progress-events-response-data-gzip.htm]
-  type: testharness
-  [XMLHttpRequest: progress events and GZIP encoding]
-    expected: FAIL
-

tests/wpt/metadata/XMLHttpRequest/security-consideration.sub.html.ini

@@ -1,5 +0,0 @@
-[security-consideration.sub.html]
-  type: testharness
-  [ProgressEvent: security consideration]
-    expected: FAIL
-

tests/wpt/metadata/XMLHttpRequest/send-response-event-order.htm.ini

@@ -1,5 +0,0 @@
-[send-response-event-order.htm]
-  type: testharness
-  [XMLHttpRequest: The send() method: event order when synchronous flag is unset]
-    expected: FAIL
-

tests/wpt/metadata/XMLHttpRequest/send-sync-response-event-order.htm.ini

@@ -1,5 +0,0 @@
-[send-sync-response-event-order.htm]
-  type: testharness
-  [XMLHttpRequest: The send() method: event order when synchronous flag is set]
-    expected: FAIL
-