test: add comment to all whatwg-url tests saying they should not be m…

[rayto510]

…odified

Checklist

• make -j4 test (UNIX), or vcbuild test (Windows) passes
• tests and/or benchmarks are included
• documentation is changed or added
• commit message follows commit guidelines

Affected core subsystem(s)

[vsemozhetbyt]

Thank you!
CI: https://ci.nodejs.org/job/node-test-pull-request/7808/

[refack]

@rayto510 Thank you for the contribution! 🥇
Two comments:

1. The commit message should follow our guidelines
2. Both the commit message and PR description should state what is the motivation for the suggesting this change

[refack]

Superseded by #12798