We introduce a typing phase into the Turbofan compilation pipeline for
wasm-gc. It has two functionalities: (1) to type nodes that were not
typed during code generation (mainly phi nodes) and (2) to narrow types
as much as possible.
The following nodes are handled, which should be enough for our
purposes: TypeGuard, WasmTypeCast, AssertNotNull, Phi, LoadFromObject,
and LoadImmutableFromObject.
Loop phi types are computed by first assigning the type of the
non-recursive input, and updating once we have the type of the recursive
inputs, and repeating this process to a fixed point.

Drive-by: Remove the narrowing of function signatures during wasm
inlining, as it created some issues and should not be needed after this
series of changes.

Bug: v8:7748
Change-Id: I8a72488d5c221c4ae8257fc5abf6f0368cf10e96
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3678208
Commit-Queue: Manos Koukoutos <manoskouk@chromium.org>
Reviewed-by: Maya Lekova <mslekova@chromium.org>
Reviewed-by: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80912}