The `go-subtest` task template wrapped the `-run` arg in single quotes
for shell safety. This works for Run Test (terminal strips quotes), but
Debug Test sends the arg through Delve’s DAP protocol with no shell
involved, so the literal quote characters ended up in the regex and
prevented any match.

All other Go task templates (`go-test`, `go-testify-suite`,
`go-table-test-case`) use the backslash-escaped format which `GoLocator`
already knows how to handle. Align the `go-subtest` template to the same
format.

Self-Review Checklist:

- [x] I've reviewed my own diff for quality, security, and reliability
- [ ] Unsafe blocks (if any) have justifying comments
- [ ] The content is consistent with the [UI/UX
checklist](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable

Closes #53230.

Release Notes:

- Fixed Debug Test for Go subtests

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Co-authored-by: Smit Barmase <heysmitbarmase@gmail.com>