Implement Object.prototype.__lookupSetter__ (#2113)

This Pull Request closes #2067

It changes the following:

- Implement `Object.prototype.__lookupSetter__`

This passes all tests from `./test262/test/built-ins/Object/prototype/__lookupSetter__/`

```
Loading the test suite...
Test suite loaded, starting tests...
Suite __lookupSetter__:
`lookup-own-get-err` (strict mode): starting
`lookup-own-get-err` (strict mode): Passed
`lookup-own-get-err`: starting
`lookup-own-get-err`: Passed
`length` (strict mode): starting
`length` (strict mode): Passed
`length`: starting
`length`: Passed
`lookup-proto-proto-err` (strict mode): starting
`lookup-proto-proto-err` (strict mode): Passed
`lookup-proto-proto-err`: starting
`lookup-proto-proto-err`: Passed
`lookup-own-acsr-wo-setter` (strict mode): starting
`lookup-own-acsr-wo-setter` (strict mode): Passed
`lookup-own-acsr-wo-setter`: starting
`lookup-own-acsr-wo-setter`: Passed
`lookup-not-found` (strict mode): starting
`lookup-not-found` (strict mode): Passed
`lookup-not-found`: starting
`lookup-not-found`: Passed
`lookup-proto-acsr-wo-setter` (strict mode): starting
`lookup-proto-acsr-wo-setter` (strict mode): Passed
`lookup-proto-acsr-wo-setter`: starting
`lookup-proto-acsr-wo-setter`: Passed
`lookup-proto-acsr-w-setter` (strict mode): starting
`lookup-proto-acsr-w-setter` (strict mode): Passed
`lookup-proto-acsr-w-setter`: starting
`lookup-proto-acsr-w-setter`: Passed
`name` (strict mode): starting
`name` (strict mode): Passed
`name`: starting
`name`: Passed
`lookup-own-acsr-w-setter` (strict mode): starting
`lookup-own-acsr-w-setter` (strict mode): Passed
`lookup-own-acsr-w-setter`: starting
`lookup-own-acsr-w-setter`: Passed
`lookup-own-proto-err` (strict mode): starting
`lookup-own-proto-err` (strict mode): Passed
`lookup-own-proto-err`: starting
`lookup-own-proto-err`: Passed
`lookup-proto-data` (strict mode): starting
`lookup-proto-data` (strict mode): Passed
`lookup-proto-data`: starting
`lookup-proto-data`: Passed
`lookup-own-data` (strict mode): starting
`lookup-own-data` (strict mode): Passed
`lookup-own-data`: starting
`lookup-own-data`: Passed
`lookup-proto-get-err` (strict mode): starting
`lookup-proto-get-err` (strict mode): Passed
`lookup-proto-get-err`: starting
`lookup-proto-get-err`: Passed
`prop-desc` (strict mode): starting
`prop-desc` (strict mode): Passed
`prop-desc`: starting
`prop-desc`: Passed
`key-invalid` (strict mode): starting
`key-invalid` (strict mode): Passed
`key-invalid`: starting
`key-invalid`: Passed
`this-non-obj` (strict mode): starting
`this-non-obj` (strict mode): Passed
`this-non-obj`: starting
`this-non-obj`: Passed

Suite __lookupSetter__ results: total: 32, passed: 32, ignored: 0, failed: 0 (panics: 0), conformance: 100.00%

Results:
Total tests: 32
Passed tests: 32
Ignored tests: 0
Failed tests: 0 (panics: 0)
Conformance: 100.00%
```

boa_engine/src/builtins/object/mod.rs

@@ -74,6 +74,7 @@ impl BuiltIn for Object {
         .method(Self::legacy_define_getter, "__defineGetter__", 2)
         .method(Self::legacy_define_setter, "__defineSetter__", 2)
         .method(Self::legacy_lookup_getter, "__lookupGetter__", 1)
+        .method(Self::legacy_lookup_setter, "__lookupSetter__", 1)
         .static_method(Self::create, "create", 2)
         .static_method(Self::set_prototype_of, "setPrototypeOf", 2)
         .static_method(Self::get_prototype_of, "getPrototypeOf", 1)
@@ -329,6 +330,50 @@ impl Object {
             }
         }
     }
+    /// `Object.prototype.__lookupSetter__(prop)`
+    ///
+    /// Returns the function bound as a getter to the specified property.
+    ///
+    /// More information:
+    ///  - [ECMAScript reference][spec]
+    ///  - [MDN documentation][mdn]
+    ///
+    /// [spec]: https://tc39.es/ecma262/#sec-object.prototype.__lookupSetter__
+    /// [mdn]: https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Object/__lookupSetter__
+    pub fn legacy_lookup_setter(
+        this: &JsValue,
+        args: &[JsValue],
+        context: &mut Context,
+    ) -> JsResult<JsValue> {
+        // 1. Let O be ? ToObject(this value).
+        let mut obj = this.to_object(context)?;
+
+        // 2. Let key be ? ToPropertyKey(P).
+        let key = args.get_or_undefined(0).to_property_key(context)?;
+
+        // 3. Repeat
+        loop {
+            // a. Let desc be ? O.[[GetOwnProperty]](key).
+            let desc = obj.__get_own_property__(&key, context)?;
+
+            // b. If desc is not undefined, then
+            if let Some(current_desc) = desc {
+                // i. If IsAccessorDescriptor(desc) is true, return desc.[[Set]].
+                return if current_desc.is_accessor_descriptor() {
+                    Ok(current_desc.expect_set().into())
+                } else {
+                    // ii. Return undefined.
+                    Ok(JsValue::undefined())
+                };
+            }
+            match obj.__get_prototype_of__(context)? {
+                // c. Set O to ? O.[[GetPrototypeOf]]().
+                Some(o) => obj = o,
+                // d. If O is null, return undefined.
+                None => return Ok(JsValue::undefined()),
+            }
+        }
+    }
 
     /// `Object.create( proto, [propertiesObject] )`
     ///