Fix requestAnimationFrame timestamps in queue

This resolves #7044 which involved callbacks
in a queue not receiving the same timestamp despite
the specification saying they should. An extra test
was added to verify the correct behavior.

tests/wpt/metadata/MANIFEST.json

@@ -28877,6 +28877,12 @@
             "path": "2dcontext/fill-and-stroke-styles/2d.fillStyle.parse.hex8.html",
             "url": "/2dcontext/fill-and-stroke-styles/2d.fillStyle.parse.hex8.html"
           }
+        ],
+        "animation-timing/same-dispatch-time.html": [
+          {
+            "path": "animation-timing/same-dispatch-time.html",
+            "url": "/animation-timing/same-dispatch-time.html"
+          }
         ]
       }
     },