Add GC zeal assertions (#12933)

* Add GC zeal assertions

- Poison freed GC objects and new heap memory
- Assert newly-allocated objects are filled with poison pattern
- Add `gc_assert!` checks for

Add GC zeal assertions (#12933)

* Add GC zeal assertions

- Poison freed GC objects and new heap memory
- Assert newly-allocated objects are filled with poison pattern
- Add `gc_assert!` checks for valid `VMGcKind` on `GcHeap::index[_mut]`
- Add `gc_assert!` checks for valid `VMGcKind` during tracing
- Add `VMGcKind::try_from_u32()` for fallible kind validation
- Add over-approximated stack roots list integrity checks, called before and
after trace and sweep. Validates kind, in-list bit, ref count, and that the
list is not cyclic.
- Add assertion that all free blocks of memory contain the poison pattern,
before and after trace and sweep

* review feedback

show more ...

Migrate the `wasmtime` crate to `wasmtime_environ::error::*` (#12231)

* Migrate the `wasmtime` crate to `wasmtime_environ::error::*`

Instead of `anyhow::Error`.

This commit re-exports the `wasmtim

Migrate the `wasmtime` crate to `wasmtime_environ::error::*` (#12231)

* Migrate the `wasmtime` crate to `wasmtime_environ::error::*`

Instead of `anyhow::Error`.

This commit re-exports the `wasmtime_environ::error` as the `wasmtime::error`
module, updates the prelude to include these new error-handling types, redirects
our top-level `wasmtime::{Error, Result}` re-exports to re-export
`wasmtime::error::{Error, Result}`, and updates various use sites that were
directly using `anyhow` to use the new `wasmtime` versions.

This process also required updating the component macro and wit-bindgen macro to
use the new error types instead of `anyhow`.

Part of https://github.com/bytecodealliance/wasmtime/issues/12069

* Replace wasmtime::error::Thing with wasmtime::Thing where it makes sense

* cargo fmt

* Move `crate::error::Thing` to `crate::Thing` where it makes sense

show more ...