Very early look into using swc instead of acorn + acorn-typescript to parse (see #13439)

So far I've just implemented parse_expression_at, which was the main blocker keeping acorn necessary. 238 test failures right now, most due to error messages not being the same, some due to hacks put in place to appease acorn-typescript.

This is really just a proof-of-concept. Instead of using swc's estree compat layer, it would be better to use their AST representation (which has full types available at @swc/types and would be compatible with their print function to avoid a dependency on esrap).

To run:

• requires nightly Rust (rustup default nightly) - this is a requirement of swc_estree_compat which could be removed by using their AST as mentioned above
• requires wasm-pack
• requires cargo-watch (cargo install cargo-watch) for dev mode
• go to packages/swc-svelte and run pnpm dev to build the rust crate

Before submitting the PR, please make sure you do the following

• It's really useful if your PR references an issue where it is discussed ahead of time. In many cases, features are absent for a reason. For large changes, please create an RFC: https://github.com/sveltejs/rfcs
• Prefix your PR title with feat:, fix:, chore:, or docs:.
• This message body should clearly illustrate what problems it solves.
• Ideally, include a test that fails without this PR but passes with it.

Tests and linting

• Run the tests with pnpm test and lint the project with pnpm lint