fix: correct handling of collapsing slashes

[ascorbic]

Changes

Multiple trailing slashes are supposed to be collapsed before applying trailing slash rules. However a regex mistake meant that it was also matching duplicate slashes that weren't trailing. This would have been a minor problem, except that in dev is was incorrectly matching against the full URL including query params, not just the path. This meant that duplicate slashes were collapsed in query params too, which is a problem when you might have https://.

This PR fixes both issues: corrects the traailing slash helper to only match trailing slashes, and ensures that the dev matching is applied to the pathname without query params

Testing

Adds a lot of tests for both dev and SSR to cover these.

Fixes #13127

Docs

[changeset-bot]

🦋 Changeset detected

Latest commit: 281ca00

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[codspeed-hq]

CodSpeed Performance Report

Merging #13130 will not alter performance

_{Comparing double-slash (281ca00) with main (2a85bd7)}

Summary

✅ 6 untouched benchmarks