Fix CI

What does this MR do?

• Uses wabt from apt instead of npm, since the latter version has unclear issues in wat2wasm for our generated code causing CI breakage
• Updates node to 18 (from 16) to enable fsPromises API
• Disables dynamically tiered compilation in V8 for benchmarks; this caused the WebAssembly benchmarks to run in unoptimized code (without this, wasm benchmarks exceed the current 20 min CI limit)

Changes to public APIs

None

Author's checklist (required)

• Intermediate commits compile (use git rebase -i main if not)
• Newly added code has a style consistent with the rest of the repository
• Newly added code is documented (guidelines)
• If bugs have been solved, tests have been added (guidelines)
• A changelog entry has been added (guidelines)

Related issues