[macos] Wrong focus behaviour with multiple Alerts

ADDITIONAL SYSTEM INFORMATION :
MacOS 10.15.3
Java 11, OpenJFX14

A DESCRIPTION OF THE PROBLEM :
This is a regression introduced by:
JDK-8227366 : Wrong stage gets focused after modal stage creation
https://bugs.java.com/bugdatabase/view_bug.do?bug_id=8227366

If you have multiple alerts opened on a parent window, pressing the escape multiple times should close each alert in the order they were opened.

This worked correctly before the above linked fix for JDK-8227366

REGRESSION : Last worked in version 13.0.2

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
* Run the attached test code which opens 3 Alerts on top of a parent Window.
* Press escape 3 times

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
All of the Alerts should have closed after pressing the escape key 3 times.
ACTUAL -
After the first press of the escape key once, the focus went to the parent Window meaning the last 2 Alerts remained open.

---------- BEGIN SOURCE ----------
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.control.Alert;
import javafx.scene.control.Alert.AlertType;
import javafx.scene.layout.BorderPane;
import javafx.stage.Stage;

public class FocusBug
{
    public static void main(
        String[] args)
    {
        Application.launch(FocusBugImpl.class);
    }
    
    public static class FocusBugImpl extends Application
    {
        private Stage mStage;
        
        @Override
        public void start(
            Stage stage) throws Exception
        {
            mStage = stage;
            final BorderPane root = new BorderPane();
            
            stage.setScene(new Scene(root, 500, 500));
            stage.show();
            
            showAlert();
            showAlert();
            showAlert();
        }
        
        private void showAlert()
        {
            final Alert alert = new Alert(AlertType.INFORMATION);
            alert.initOwner(mStage);
            alert.show();
        }
    }
    
}
---------- END SOURCE ----------

FREQUENCY : always