Add BigInt objects to structured cloning test

BigInts were missing on the structured clone test although it was defined in the HTML specification.

Author: BasixKOR

IndexedDB/structured-clone.any.js

@@ -120,7 +120,7 @@ const strings = [
   }));
 
 // "Primitive" Objects (Boolean, Number, BigInt, String)
-[].concat(booleans, numbers, strings)
+[].concat(booleans, numbers, bigints, strings)
   .forEach(value => cloneObjectTest(Object(value), (orig, clone) => {
     assert_equals(orig.valueOf(), clone.valueOf());
   }));