These are part of the typed function references proposal, which is now
widely used by toolchains like wasm-bindgen. This makes sites like
wordsalad.online load in Ladybird.
The typed function references proposal requires subtype checking: e.g.
(ref $t) is a subtype of (ref func), and a non-nullable reference is a
subtype of its nullable counterpart. This is needed for correct
validation of `call_ref` and `return_call_ref`.
This adds parsing of `(ref typeidx)` and validates that `typeidx` is a
valid index. Currently, nullability of the reference is lost.
A bug causing the code below to fail parsing has been fixed.
```wat
(module
(type $T (struct (field i32) (field f32)))
(type $T1 (struct (field i32) (field f32)))
(; many more types... ;)
(type $T64 (struct (field i32) (field f32)))
(type $f (func (result (ref null $T64))))
)
```
The spec tests type-equivalence.{0,1,3,13} have been disabled as they
were previously false positives.
This patch adds support for parsing structs in the type section.
It also removes the assumption that all types in the type section are
function types, adding appropriate validation.
Spec tests struct.3 and struct.4 have been disable as this would
require expanding `ValueType` to include more heap-types.
Since memory64 got merged into the spec the minimum value for limits
is now actualy 64-bit and the maximum sizes for memories and tables
for I64 address types were increased.
Fixes 5 tests in memory64.wast nad 8 tests in table64.wast on WPT.
Namely, find an upper bound at validation time so we can allocate the
space when entering the frame.
Also drop labels at once instead of popping them off one at a time now
that we're using a Vector.
