Trying clear coat validation test with gltf instead of glb file

tests/validation/config.json

@@ -605,7 +605,7 @@
         },
         {
             "title": "GLTF ClearCoat",
-            "playgroundId": "#YG3BBF#3",
+            "playgroundId": "#YG3BBF#4",
             "referenceImage": "glTFClearCoat.png",
             "renderCount": 10
         },