Use the new feature of Go 1.24, fix linter warnings.
This change was produced by:
- running golangci-lint run --fix
- sed 's/context.Background/t.Context/' -i `git grep -l context.Background | grep test.go`
- manually fixing broken tests
- itest, lntest: use ht.Context() where ht or hn is available
- in HarnessNode.Stop() we keep using context.Background(), because it is
called from a cleanup handler in which t.Context() is canceled already.
The package provides type GoroutineManager which is used to launch goroutines
until context expires or the manager is stopped. Stop method blocks until all
started goroutines stop.
Original code by Andras https://go.dev/play/p/HhRpE-K2lA0
Adjustments and tests by Boris.
Boris Nagaev