rust-url's debugger_visualizer tests are broken in rustc nightly-2024-08-13

[valenting]

I was looking into servo/rust-url#967 but I wasn't able to reproduce the failures locally. Then I realized I was running an older nightly.

I used bisect-rustc and got the following output:

---

searched nightlies: from nightly-2024-08-01 to nightly-2024-09-16
regressed nightly: nightly-2024-08-13
searched commit range: 41dd149...91376f4
regressed commit: 13f8a57

bisected with cargo-bisect-rustc v0.6.9

Host triple: x86_64-pc-windows-msvc
Reproduce with:

cargo bisect-rustc --start=2024-08-01 --end=2024-09-16 --test-dir=rust-url -- test --test debugger_visualizer --features url/debugger_visualizer,url_debug_tests/debugger_visualizer -- --test-threads=1 --nocapture

---

The PR that introduced the issue seems to be: #126793

Example failing job: https://github.com/servo/rust-url/actions/runs/10879435038/job/30184131451

[jieyouxu]

cc @saethlin since you authored #126793 and are more familiar with debuggers