script: Implement creating and running classic scripts according to spec (#41109)

Implemented spec algorithms [create a classic
script](https://html.spec.whatwg.org/multipage/#creating-a-classic-script)
and [run a classic
script](https://html.spec.whatwg.org/multipage/#run-a-classic-script).
Classic script now gets unminified on creation.

Testing: Behaviour hasn't changed much, but we pass a new test instead
of crashing.

---------

Signed-off-by: Gae24 <96017547+Gae24@users.noreply.github.com>

components/script/script_module.rs

@@ -104,7 +104,11 @@ impl ModuleObject {
 pub(crate) struct RethrowError(RootedTraceableBox<Heap<JSVal>>);
 
 impl RethrowError {
-    fn handle(&self) -> Handle<'_, JSVal> {
+    pub(crate) fn new(val: Box<Heap<JSVal>>) -> Self {
+        Self(RootedTraceableBox::from_box(val))
+    }
+
+    pub(crate) fn handle(&self) -> Handle<'_, JSVal> {
         self.0.handle()
     }
 }