Split pbr coverage test into 3 tests

tests/validation/config.json

@@ -677,9 +677,19 @@
             "referenceImage": "pbr_refraction.png"
         },
         {
-            "title": "PBR shader code coverage",
-            "playgroundId": "#QI7TL3#3",
-            "referenceImage": "pbr_codecoverage.png"
+            "title": "PBR shader code coverage #1",
+            "playgroundId": "#QI7TL3#4",
+            "referenceImage": "pbr_codecoverage1.png"
+        },
+        {
+            "title": "PBR shader code coverage #2",
+            "playgroundId": "#QI7TL3#6",
+            "referenceImage": "pbr_codecoverage2.png"
+        },
+        {
+            "title": "PBR shader code coverage #3",
+            "playgroundId": "#QI7TL3#7",
+            "referenceImage": "pbr_codecoverage3.png"
         },
         {
             "title": "Texture cache",