interrupt process on windows as well

On Windows, the killing of running services relies on the
60 second kill timeout, making it faster to restart the harness
to force rebuilding.

Since os.Interrupt works for me, remove the runtime os check in
harness/app.go completely.

harness/app.go

@@ -11,7 +11,6 @@ import (
 	"io"
 	"os"
 	"os/exec"
-	"runtime"
 	"sync"
 	"time"
 
@@ -133,11 +132,8 @@ func (cmd AppCmd) Kill() {
 
 		// Send an interrupt signal to allow for a graceful shutdown
 		utils.Logger.Info("Killing revel server pid", "pid", cmd.Process.Pid)
-		var err error
-		if runtime.GOOS != "windows" {
-			// os.Interrupt is not available on windows
-			err = cmd.Process.Signal(os.Interrupt)
-		}
+
+		err := cmd.Process.Signal(os.Interrupt)
 
 		if err != nil {
 			utils.Logger.Info(