We would previously not return a RadioNodeList in the curious case where
a named item resolves to two different elements within the form.
This was not a problem when calling namedItem directly in the IDL as
named_item_or_radio_node_list shadows named_item but is exposed when
calling the property through array bracket notation (as an example).
Fix this, and add a bunch more tests to cover
HTMLFormControlsCollection.
This allows us to improve the const-correctness in RadioNodeList, which
has been made possible as of: 5f0ccfb499 now that a GC-visit accepts a
const GC pointer.
With this change, we now have ~1200 CellAllocators across both LibJS and
LibWeb in a normal WebContent instance.
This gives us a minimum heap size of 4.7 MiB in the scenario where we
only have one cell allocated per type. Of course, in practice there will
be many more of each type, so the effective overhead is quite a bit
smaller than that in practice.
I left a few types unconverted to this mechanism because I got tired of
doing this. :^)
