Add auto logging of goroutine pid label (#19212)

Add auto logging of goroutine pid label (#19212)

* Add auto logging of goroutine pid label

This PR uses unsafe to export the hidden runtime_getProfLabel function from the
runtime package and then casts the result to a map[string]string.

We can then interrogate this map to get the pid label from the goroutine allowing
us to log it with any logging request.

Reference #19202

Signed-off-by: Andrew Thornton <art27@cantab.net>