Clean target directories of linux builders.
This should avoid our frequent problems with running out of disk space on the smallest linux build machines. This linux builders are also our fastest ones, so it shouldn't slow down our CI too much.
<!-- 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/20085)
<!-- Reviewable:end -->
Minor cleanup of element.innerText
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
<!-- 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/20080)
<!-- Reviewable:end -->
Added extra bool in Window object to know about its Mutation Observers
<!-- Please describe your changes on the following line: -->
- Added Cell<bool> type variable in Window object to know whether its mutation observers are present/absent
- Added get and set functions for this variable
- Added supporting test files to check for performance
---
<!-- 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#16936.
<!-- Either: -->
- [x] There are tests for these changes, but these are manual tests for checking correctness of added code
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- 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/20041)
<!-- Reviewable:end -->
style: Make XBL / Shadow DOM use something more light-weight than a Stylist.
Introduce AuthorStyles, which is just a struct aggregating stylesheets +
CascadeData, with a quirks_mode parameter because XBL sucks so bad.
Bug: 1436059
Reviewed-by: xidorn
MozReview-Commit-ID: 7q99tSNXo0K
<!-- 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/20061)
<!-- Reviewable:end -->
It's just a struct aggregating stylesheets + CascadeData, with a quirks_mode
parameter because XBL sucks so bad.
Bug: 1436059
Reviewed-by: xidorn
MozReview-Commit-ID: 7q99tSNXo0K
Implement element.innerText setter
- [X] `./mach build -d` does not report any errors
- [X] `./mach test-tidy` does not report any errors
- [X] These changes fix#16107
- [X] There are tests for these changes
<!-- 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/20054)
<!-- Reviewable:end -->
It only has one use, has the same effect that "auto", and should have no effect
in <a> elements anyway (plus it's not overridden or used in that file at all
anyway), so we can remove its only use instead.
I can also change that use to "auto" if you want, but bug 760876 doesn't mention
-moz-user-input at all, so I think this is quite useless...
See the intent to unship for research on out of the tree usage:
https://groups.google.com/d/msg/mozilla.dev.platform/E6tfP__wkwg/YVW6nPX9CQAJ
Bug: 1405087
Reviewed-by: bz
MozReview-Commit-ID: 8EzQlzu9drE
Adding left over tests using DRY coding
<!-- 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 add the tests using DRY technique to reduce redundant code for https://github.com/servo/servo/pull/19963
<!-- Also, please make sure that "Allow edits from maintainers" checkbox is checked, so that we can help you if you get stuck somewhere along the way.-->
<!-- 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/20050)
<!-- Reviewable:end -->