LibJS: Implement WeakRef changes from 'Symbol as WeakMap Keys Proposal'

Author: https://github.com/IdanHo
Commit: 53ed8decaf
Pull-request: https://github.com/SerenityOS/serenity/pull/14361
Reviewed-by: https://github.com/alimpfard ✅
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibJS/Tests/builtins/WeakRef/WeakRef.js

@@ -8,7 +8,7 @@ describe("errors", () => {
         [-100, Infinity, NaN, 152n, undefined].forEach(value => {
             expect(() => {
                 new WeakRef(value);
-            }).toThrowWithMessage(TypeError, "is not an object");
+            }).toThrowWithMessage(TypeError, "cannot be held weakly");
         });
     });
     test("called without new", () => {
@@ -27,4 +27,9 @@ describe("normal behavior", () => {
         var a = new WeakRef({});
         expect(a instanceof WeakRef).toBeTrue();
     });
+
+    test("constructor with single symbol argument", () => {
+        var a = new WeakRef(Symbol());
+        expect(a instanceof WeakRef).toBeTrue();
+    });
 });