Remove wasm-gc from RustAsset

[DeMoorJasper]

---

name: 🙋 New Pull Request
about: Do you want to change something on parcel?

↪️ Pull Request

rustc is now able to handle everything wasm-gc did according to the readme of wasm-gc therefore I made this PR removing wasm-gc.

💻 Examples

✔️ PR Todo

• Added/updated unit tests for this change
• Filled out test instructions
• Included links to related issues/PRs

[devongovett]

readme also mentions a --gc-sections flag that the rust compiler supports. do we need to use that?

[devongovett]

cc @alexcrichton

[alexcrichton]

Looks good to me! It's true that wasm-gc is no longer needed, and the Rust compiler automatically by default executes the equivalent of --gc-sections when creating output, so no need to pass any extra flags either!