The spec language specifies 'Set maxScopeString to "/", followed by the
strings in XXXX’s path (including empty strings), separated from each
other by "/"': That is, adjacent components are separated by a '/', but
the last component does not get a trailing '/'.
This resulted in the generated scope string ending with '//' in some
cases, incorrectly tripping the 'Service-Worker-Allowed' security check
Resulting in a massive rename across almost everywhere! Alongside the
namespace change, we now have the following names:
* JS::NonnullGCPtr -> GC::Ref
* JS::GCPtr -> GC::Ptr
* JS::HeapFunction -> GC::Function
* JS::CellImpl -> GC::Cell
* JS::Handle -> GC::Root
Now that the heap has no knowledge about a JavaScript realm and is
purely for managing the memory of the heap, it does not make sense
to name this function to say that it is a non-realm variant.
