internal/gocommand: tweak debugging for hanging go commands

Add a TODO and wait for a shorter period of time following Kill, per
post-submit advice from bcmills on CL 424075.

For golang/go#54461

Change-Id: Ia0e388c0119660844dad32629ebca4f122fded12
Reviewed-on: https://go-review.googlesource.com/c/tools/+/431075
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Robert Findley <rfindley@google.com>
gopls-CI: kokoro <noreply+kokoro@google.com>
Reviewed-by: Bryan Mills <bcmills@google.com>

Author: findleyr

internal/gocommand/invoke.go

@@ -276,18 +276,21 @@ func runCmdContext(ctx context.Context, cmd *exec.Cmd) error {
 		return err
 	case <-time.After(time.Second):
 	}
+
 	// Didn't shut down in response to interrupt. Kill it hard.
+	// TODO(rfindley): per advice from bcmills@, it may be better to send SIGQUIT
+	// on certain platforms, such as unix.
 	if err := cmd.Process.Kill(); err != nil && DebugHangingGoCommands {
 		// Don't panic here as this reliably fails on windows with EINVAL.
 		log.Printf("error killing the Go command: %v", err)
 	}
 
-	// See above: only wait for a minute if we're debugging hanging Go commands.
+	// See above: don't wait indefinitely if we're debugging hanging Go commands.
 	if DebugHangingGoCommands {
 		select {
 		case err := <-resChan:
 			return err
-		case <-time.After(1 * time.Minute):
+		case <-time.After(10 * time.Second): // a shorter wait as resChan should return quickly following Kill
 			HandleHangingGoCommand()
 		}
 	}