WebIDL: Add tests for function property enumeration order

webidl/ecmascript-binding/builtin-function-properties.any.js

@@ -0,0 +1,23 @@
+"use strict";
+
+test(() => {
+  const ownPropKeys = Reflect.ownKeys(Blob).slice(0, 3);
+  assert_array_equals(ownPropKeys, ["length", "name", "prototype"]);
+}, 'Constructor property enumeration order of "length", "name", and "prototype"');
+
+test(() => {
+  assert_own_property(Blob.prototype, "slice");
+
+  const ownPropKeys = Reflect.ownKeys(Blob.prototype.slice).slice(0, 2);
+  assert_array_equals(ownPropKeys, ["length", "name"]);
+}, 'Method property enumeration order of "length" and "name"');
+
+test(() => {
+  assert_own_property(Blob.prototype, "size");
+
+  const desc = Reflect.getOwnPropertyDescriptor(Blob.prototype, "size");
+  assert_equals(typeof desc.get, "function");
+
+  const ownPropKeys = Reflect.ownKeys(desc.get).slice(0, 2);
+  assert_array_equals(ownPropKeys, ["length", "name"]);
+}, 'Getter property enumeration order of "length" and "name"');