Revert "use newer acorn version for bundling, to support newer JS syntax"

This reverts commit b142a3d.

Author: emilykl

package-lock.json

@@ -182,10 +182,5 @@
     "transform-loader": "^0.2.4",
     "true-case-path": "^2.2.1",
     "virtual-webgl": "^1.0.6"
-  },
-  "overrides": {
-    "falafel": {
-      "acorn": "^8.1.1"
-    }
   }
-}
+}