Auto merge of #19875 - asajeffrey:test-perf-use-https-for-git-clone, r=jdm

Use https github URL to clone servo-warc-tests repo

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

Fixes timeouts such as http://build.servo.org/builders/linux-nightly/builds/583/steps/test/logs/stdio caused by github.com not being in the ssh known hosts.

---
<!-- 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 do not require tests because this is test infrastructure

<!-- 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/19875)
<!-- Reviewable:end -->

0 files changed, 0 insertions, 0 deletions