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 -->
Fix loss of response type information in Fetch API
<!-- Please describe your changes on the following line: -->
Avoids mapping response types that are distinct according to [the spec](https://fetch.spec.whatwg.org/#concept-response-type) to fewer response types. Also updates test expectations to match that we now pass tests that check the response type.
---
<!-- 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#14068
<!-- Either: -->
- [X] There are tests for these changes
<!-- 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/14868)
<!-- Reviewable:end -->
Implemented XMLHttpRequest.send(Document)
<!-- Please describe your changes on the following line: -->
---
<!-- 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#9490 .
<!-- Either: -->
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.
```
<!-- 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/14648)
<!-- Reviewable:end -->
It could be used to have mutable JSVal fields without GC barriers.
With the removal of that trait, MutHeap and MutNullableHeap can respectively
be replaced by MutJS and MutNullableJS.
Implement range index with the Position enum on ServoUrl
<!-- Please describe your changes on the following line: -->
---
<!-- 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
- [ ] These changes fix #__ (github issue number if applicable).
<!-- Either: -->
- [ ] There are tests for these changes OR
- [X] These changes do not require tests because refactoring
<!-- Pull requests that do not address these steps are welcome, but they will require additional verification as part of the review process. -->
r? @emilio
<!-- 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/14274)
<!-- Reviewable:end -->
Urlmageddon
<!-- Please describe your changes on the following line: -->
Still needs a bunch of code in net to be converted in order to get more
advantage of this for images and stuff, but meanwhile this should help quite a
bit with #13778.
Still wanted to get this in.
r? @SimonSapin
<!-- 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/14246)
<!-- Reviewable:end -->
11485 make dom methods taking mut js content unsafe
This is a rebased version of PR #11595
---
<!-- 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#11485
<!-- Either: -->
- [ ] There are tests for these changes OR
- [x] These changes do not require tests because: no code logic was changed
<!-- 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/14096)
<!-- Reviewable:end -->
Free-standing fonctions parse_html and friends are now static methods
on ServoParser, and the HTML and XML tokenizers have been moved to private
submodules.
