Improving BitmapData.draw performance (in dispose Image mode)

[rainyt]

1. Referencing the OpenGLRenderer renderer eliminates the need for reconstruction and reduces the cost of initializing the Shader.

2. Set default shaders for existing OpenGLRenderer renderers.

It is very effective in the following code:

package;

import openfl.geom.Matrix;
import openfl.display.FPS;
import openfl.events.Event;
import openfl.display.BitmapData;
import openfl.display.Bitmap;
import openfl.display.Sprite;

class Main extends Sprite {
	public function new() {
		super();

		var spr = new Sprite();
		spr.graphics.beginFill(0xff0000);
		spr.graphics.drawCircle(0, 0, 10);
		spr.graphics.endFill();

		var drawBitmapData = new BitmapData(500, 500, false, 0);
		drawBitmapData.disposeImage();

		var drawBitmap = new Bitmap(drawBitmapData);
		this.addChild(drawBitmap);

		this.addEventListener(Event.ENTER_FRAME, (e) -> {
			var m = new Matrix();
			m.translate(Math.random() * 500, Math.random() * 500);
			for (i in 0...100) {
				drawBitmapData.draw(spr, m);
			}
		});

		var fps = new FPS();
		this.addChild(fps);
	}
}