Made instance recording symmetrical between construct and dispose for Engine. (#8685)

src/Engines/engine.ts

@@ -483,14 +483,14 @@ export class Engine extends ThinEngine {
     constructor(canvasOrContext: Nullable<HTMLCanvasElement | WebGLRenderingContext>, antialias?: boolean, options?: EngineOptions, adaptToDeviceRatio: boolean = false) {
         super(canvasOrContext, antialias, options, adaptToDeviceRatio);
 
+        Engine.Instances.push(this);
+
         if (!canvasOrContext) {
             return;
         }
 
         options = this._creationOptions;
 
-        Engine.Instances.push(this);
-
         if ((<any>canvasOrContext).getContext) {
             let canvas = <HTMLCanvasElement>canvasOrContext;