proposal: runtime/pprof,runtime: add new goroutine leak profile as a GOEXPERIMENT

[mknyszek]

This is a mini-proposal to land the work powering #74609 behind a new GOEXPERIMENT, goleakprofiler, so

1. The implementation CL can stop accumulating merge conflicts,
2. More people can try it out.

RE: (2), I think we actually already have a substantial amount of evidence that this is widely applicable. The extensive test suite added in go.dev/cl/688335 includes minimized versions of real leaks found in real-world large scale Go programs in the wild. The main reason here is (1).

[gabyhelp]

Related Issues

• proposal: runtime/pprof,runtime: new goroutine leak profile #74609

_{(Emoji vote if this was helpful or unhelpful; more detailed feedback welcome in this discussion.)}