Before this change, we were going through the chain of base classes for
each IDL interface object and having them set the prototype to their
prototype.
Instead of doing that, reorder things so that we set the right prototype
immediately in Foo::initialize(), and then don't bother in all the base
class overrides.
This knocks off a ~1% profile item on Speedometer 3.
The main streams AO file has gotten very large, and is a bit difficult
to navigate. In an effort to improve DX, this migrates TransformStream
AOs to their own file.
Required by the server-side rendering mode of React Router, used by
https://chatgpt.com/
Note that the imported tests do not have the worker variants to prevent
freezing on macOS.
