fix: don't fail host steps over a leftover holding their output (#1323)

A successful host step whose background child kept its output open failed with `exec: WaitDelay expired before I/O complete`. Like GitHub's runner (`ProcessExitedHandler` in https://github.com/actions/runner/blob/main/src/Runner.Sdk/ProcessInvoker.cs), the step now succeeds after the drain timeout.

The leftover is killed only on Windows, as GitHub does there. A step whose timeout or cancellation hits during the drain still fails.

Fixes: https://gitea.com/gitea/runner/issues/1290
Co-authored-by: bircni <[email protected]>
Reviewed-on: https://gitea.com/gitea/runner/pulls/1323
Reviewed-by: bircni <[email protected]>
Co-authored-by: silverwind <[email protected]>

act/container/host_environment.go

@@ -338,7 +338,7 @@ func (e *HostEnvironment) exec(ctx context.Context, command []string, cmdline st
 	} else {
 		defer k.Close()
 	}
-	err = cmd.Wait()
+	err = treeKill.Wait(ctx, cmd)
 	if err != nil {
 		if exitErr, ok := errors.AsType[*exec.ExitError](err); ok {
 			return ExitCodeError(exitErr.ExitCode())