runtime: scheduler change causes Delve's function call injection to fail intermittently [1.21 backport]

[gopherbot]

@mknyszek requested issue #61732 to be considered for backport to the next 1.21 minor release.

Ha, OK. Backport it is.

@gopherbot Please open a backport issue for Go 1.21. This issue causes significant debugger friction due to an issue that was latent in earlier releases but only really started cropping up in Go 1.21 due to a scheduler change in that release. The fix is very low risk, since it only impacts the debugger function call protocol, which should have no impact on production applications. The fix is also fairly small and straightforward.

[gopherbot]

Change https://go.dev/cl/526576 mentions this issue: [release-branch.go1.21] runtime: always lock OS thread in debugcall

[gopherbot]

Closed by merging 0b6b0a2 to release-branch.go1.21.