Wasmtime(gc): Support `(ref.i31 (global.get $g))` const expressions #22926

Job	Run time
Rustfmt	37s
Clang format	11s
Determine CI jobs to run	4s
Check	9m 23s
Cargo deny	30s
Cargo vet	29s
Build wasi-preview1-component-adapter	0s
Check Windows ARM64	0s
Doc build	0s
Test Linux x86_64	16m 58s
Test C-API ${{ matrix.os }}	0s
Nightly tests	0s
Run benchmarks	0s
Release build for ${{ matrix.build }}	0s
Build wasmtime-target-wasm32	0s
Meta deterministic check	0s
Miri	0s
verify-publish	0s
Cargo vet failed on a Pull Request	0s
Record the result of testing and building steps	1s
push-tag	0s
	28m 13s

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