runtime,time: timer.Stop returns false even when no value is read from the channel [1.23 backport]

[gopherbot]

@ianlancetaylor requested issue #69312 to be considered for backport to the next 1.23 minor release.

@gopherbot Please open a backport to 1.23.

This bug makes it difficult or impossible to write timer code that uses Stop and Reset and works correctly for all versions of Go.

[cagedmantis]

This is approved as it is a bug without a workaround.

[gopherbot]

Change https://go.dev/cl/616096 mentions this issue: [release-branch.go1.23] runtime: if stop/reset races with running timer, return correct result

[gopherbot]

Closed by merging CL 616096 (commit 3b2e846) to release-branch.go1.23.

[gopherbot]

Change https://go.dev/cl/617596 mentions this issue: [release-branch.go1.23] runtime: clear isSending bit earlier