time,runtime: too many concurrent timer firings for short `time.Ticker` [1.23 backport]

[gopherbot]

@mknyszek requested issue #69880 to be considered for backport to the next 1.23 minor release.

@gopherbot Please open a backport issue for Go 1.23.

This is a serious issue that affects users with no reasonable workaround. This issues does not affect Go 1.22.

[gopherbot]

Change https://go.dev/cl/620137 mentions this issue: [release-branch.go1.23] runtime: don't frob isSending for tickers

[gopherbot]

Closed by merging CL 620137 (commit 8d79bf7) to release-branch.go1.23.

[gopherbot]

Change https://go.dev/cl/621856 mentions this issue: [release-branch.go1.23] runtime,time: use atomic.Int32 for isSending