MessagePort: implement disentanglement (#36654)

Implement
[disentangle](https://html.spec.whatwg.org/multipage/#disentangle)
Remove bespoke gc logic which now becomes unnecessary. 
Adds a wpt test that hits the "disentangle while in transfer" logic.
Updates streams code, fixing an error where disentanglement is
conditional on an error.

Test coverage: there are existing tests in
`/webmessaging/message-channels/close-event/explicitly-closed.tentative.window.js`
for the no transfer case, and the simple completed transfer case, and
this PR adds a test for the more complicated transfer in progress case.

Fix https://github.com/servo/servo/issues/36465

---------

Signed-off-by: gterzian <2792687+gterzian@users.noreply.github.com>

components/script_bindings/codegen/Bindings.conf

@@ -474,7 +474,7 @@ DOMInterfaces = {
 
 'MessagePort': {
     'weakReferenceable': True,
-    'canGc': ['GetOnmessage'],
+    'canGc': ['Close', 'GetOnmessage', 'SetOnmessage', 'Start'],
 },
 
 'MessageEvent': {

components/script_bindings/webidls/MessagePort.webidl

@@ -16,6 +16,7 @@ interface MessagePort : EventTarget {
   // event handlers
   attribute EventHandler onmessage;
   attribute EventHandler onmessageerror;
+  attribute EventHandler onclose;
 };
 
 dictionary StructuredSerializeOptions {