Remove wasmtime-environ's dependency on cranelift-codegen (#3199)

* Move `CompiledFunction` into wasmtime-cranelift

This commit moves the `wasmtime_environ::CompiledFunction` type into the
`wasmtime-cranelift` crate. This type has lots of Cranelift-specific
pieces of compilation and doesn't need to be generated by all Wasmtime
compilers. This replaces the usage in the `Compiler` trait with a
`Box<Any>` type that each compiler can select. Each compiler must still
produce a `FunctionInfo`, however, which is shared information we'll
deserialize for each module.

The `wasmtime-debug` crate is also folded into the `wasmtime-cranelift`
crate as a result of this commit. One possibility was to move the
`CompiledFunction` commit into its own crate and have `wasmtime-debug`
depend on that, but since `wasmtime-debug` is Cranelift-specific at this
time it didn't seem like it was too too necessary to keep it separate.
If `wasmtime-debug` supports other backends in the future we can
recreate a new crate, perhaps with it refactored to not depend on
Cranelift.

* Move wasmtime_environ::reference_type

This now belongs in wasmtime-cranelift and nowhere else

* Remove `Type` reexport in wasmtime-environ

One less dependency on `cranelift-codegen`!

* Remove `types` reexport from `wasmtime-environ`

Less cranelift!

* Remove `SourceLoc` from wasmtime-environ

Change the `srcloc`, `start_srcloc`, and `end_srcloc` fields to a custom
`FilePos` type instead of `ir::SourceLoc`. These are only used in a few
places so there's not much to lose from an extra abstraction for these
leaf use cases outside of cranelift.

* Remove wasmtime-environ's dep on cranelift's `StackMap`

This commit "clones" the `StackMap` data structure in to
`wasmtime-environ` to have an independent representation that that
chosen by Cranelift. This allows Wasmtime to decouple this runtime
dependency of stack map information and let the two evolve
independently, if necessary.

An alternative would be to refactor cranelift's implementation into a
separate crate and have wasmtime depend on that but it seemed a bit like
overkill to do so and easier to clone just a few lines for this.

* Define code offsets in wasmtime-environ with `u32`

Don't use Cranelift's `binemit::CodeOffset` alias to define this field
type since the `wasmtime-environ` crate will be losing the
`cranelift-codegen` dependency soon.

* Commit to using `cranelift-entity` in Wasmtime

This commit removes the reexport of `cranelift-entity` from the
`wasmtime-environ` crate and instead directly depends on the
`cranelift-entity` crate in all referencing crates. The original reason
for the reexport was to make cranelift version bumps easier since it's
less versions to change, but nowadays we have a script to do that.
Otherwise this encourages crates to use whatever they want from
`cranelift-entity` since  we'll always depend on the whole crate.

It's expected that the `cranelift-entity` crate will continue to be a
lean crate in dependencies and suitable for use at both runtime and
compile time. Consequently there's no need to avoid its usage in
Wasmtime at runtime, since "remove Cranelift at compile time" is
primarily about the `cranelift-codegen` crate.

* Remove most uses of `cranelift-codegen` in `wasmtime-environ`

There's only one final use remaining, which is the reexport of
`TrapCode`, which will get handled later.

* Limit the glob-reexport of `cranelift_wasm`

This commit removes the glob reexport of `cranelift-wasm` from the
`wasmtime-environ` crate. This is intended to explicitly define what
we're reexporting and is a transitionary step to curtail the amount of
dependencies taken on `cranelift-wasm` throughout the codebase. For
example some functions used by debuginfo mapping are better imported
directly from the crate since they're Cranelift-specific. Note that
this is intended to be a temporary state affairs, soon this reexport
will be gone entirely.

Additionally this commit reduces imports from `cranelift_wasm` and also
primarily imports from `crate::wasm` within `wasmtime-environ` to get a
better sense of what's imported from where and what will need to be
shared.

* Extract types from cranelift-wasm to cranelift-wasm-types

This commit creates a new crate called `cranelift-wasm-types` and
extracts type definitions from the `cranelift-wasm` crate into this new
crate. The purpose of this crate is to be a shared definition of wasm
types that can be shared both by compilers (like Cranelift) as well as
wasm runtimes (e.g. Wasmtime). This new `cranelift-wasm-types` crate
doesn't depend on `cranelift-codegen` and is the final step in severing
the unconditional dependency from Wasmtime to `cranelift-codegen`.

The final refactoring in this commit is to then reexport this crate from
`wasmtime-environ`, delete the `cranelift-codegen` dependency, and then
update all `use` paths to point to these new types.

The main change of substance here is that the `TrapCode` enum is
mirrored from Cranelift into this `cranelift-wasm-types` crate. While
this unfortunately results in three definitions (one more which is
non-exhaustive in Wasmtime itself) it's hopefully not too onerous and
ideally something we can patch up in the future.

* Get lightbeam compiling

* Remove unnecessary dependency

* Fix compile with uffd

* Update publish script

* Fix more uffd tests

* Rename cranelift-wasm-types to wasmtime-types

This reflects the purpose a bit more where it's types specifically
intended for Wasmtime and its support.

* Fix publish script

Cargo.toml

@@ -23,7 +23,6 @@ doc = false
 [dependencies]
 wasmtime = { path = "crates/wasmtime", version = "0.29.0", default-features = false, features = ['cache'] }
 wasmtime-cache = { path = "crates/cache", version = "0.29.0" }
-wasmtime-debug = { path = "crates/debug", version = "0.29.0" }
 wasmtime-environ = { path = "crates/environ", version = "0.29.0" }
 wasmtime-jit = { path = "crates/jit", version = "0.29.0" }
 wasmtime-wast = { path = "crates/wast", version = "0.29.0" }
@@ -43,7 +42,6 @@ rayon = "1.5.0"
 humantime = "2.0.0"
 wasmparser = "0.80.0"
 lazy_static = "1.4.0"
-cranelift-native = { path = 'cranelift/native', version = '0.76.0' }
 
 [dev-dependencies]
 env_logger = "0.8.1"