Integrate re-init hook

[logan-gatlin]

Simplifies the shim code for the panic=unwind path using the new wasm-bindgen reinit hook. I created a new shim file for panic unwind builds that handles incrementing the instanceId and setting the panic error hook in Rust.

[guybedford]

In theory this should now fix this test - https://github.com/cloudflare/workers-rs/blob/main/test/tests/panic.spec.ts#L183.

Can we try that out on this PR?

[codspeed-hq]

Merging this PR will not alter performance

⚠️ Unknown Walltime execution environment detected

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For the most accurate results, we recommend using CodSpeed Macro Runners: bare-metal machines fine-tuned for performance measurement consistency.

✅ 2 untouched benchmarks

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_{Comparing reinit-hook (df2411f) with main (f9d380b)}