Return out of windows signal handler

Signed-off-by: Michael Crosby <crosbymichael@gmail.com>

runtime/v2/shim/shim_windows.go

@@ -113,6 +113,7 @@ func handleSignals(logger *logrus.Entry, signals chan os.Signal) error {
 		for s := range signals {
 			switch s {
 			case os.Interrupt:
+				return nil
 			}
 		}
 	}