Revert "Improve Loader closure performance"

This reverts commit bdef09a91e2aaadde02e62fea7bc3f78f0fbd52e.

src/loaders/Loader.js

@@ -106,12 +106,14 @@ Object.assign( Loader.prototype, {
 			CustomBlending: CustomBlending
 		};
 
-		var color = new Color();
-		var textureLoader = new TextureLoader();
-		var materialLoader = new MaterialLoader();
+		var color, textureLoader, materialLoader;
 
 		return function createMaterial( m, texturePath, crossOrigin ) {
 
+			if ( color === undefined ) color = new Color();
+			if ( textureLoader === undefined ) textureLoader = new TextureLoader();
+			if ( materialLoader === undefined ) materialLoader = new MaterialLoader();
+
 			// convert from old material format
 
 			var textures = {};