Similar to #19865
r? jdm
Note: Should I squash all the commits into one commit?
---
- [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 it should not break anything
Source-Repo: https://github.com/servo/servo
Source-Revision: c9ba16f9fbdf7f43cb19feedfaaa68c85bbcbe3b
(Do not merge) Merge some test crates in their corresponding components
Source-Repo: https://github.com/servo/servo
Source-Revision: a4808a3649e6cb6e579e60b82d9979755643f711