kill process instead of sending SIGTERM on Windows (#3304)

xray/process.go

@@ -239,7 +239,12 @@ func (p *process) Stop() error {
 	if !p.IsRunning() {
 		return errors.New("xray is not running")
 	}
-	return p.cmd.Process.Signal(syscall.SIGTERM)
+	
+	if runtime.GOOS == "windows" {
+		return p.cmd.Process.Kill()
+	} else {
+		return p.cmd.Process.Signal(syscall.SIGTERM)
+	}
 }
 
 func writeCrashReport(m []byte) error {