Remove unnecessary conditional definition of `FS_WATCH_LATENCY` (#26967)

This was added in #8343 to make it only visible for tests. #9189 then
made it visible regardless of `test-support`, so the definitions became
identical.

Release Notes:

- N/A
1139904ef5Michael Sloan committed on 3/18/2025, 4:10:16 AM· committed by GitHubparentb4ef379
1 file changedLine totals unavailable