Replace std::collections::HashMap with rustc_hash::FxHashMap

[hardfist]

This is all automatic generated by copilot agent
This commit replaces all usages of std::collections::HashMap with rustc_hash::FxHashMap throughout the rspack codebase for better performance.

FxHashMap provides significantly better performance for string keys and is already widely used in the Rust ecosystem for performance-critical applications like rustc itself.

Changes:

• Replace import statements: std::collections::HashMap -> rustc_hash::FxHashMap as HashMap
• Update type annotations to use FxHashMap
• Add rustc-hash dependency to crates that needed it
• Handle special cases where external APIs (like LightningCSS) still require std HashMap
• Update HashMap construction from ::new() to ::default() where needed

All tests pass and compilation succeeds with these changes.

Summary

Checklist

• Tests updated (or not required).
• Documentation updated (or not required).

[codspeed-hq]

CodSpeed Performance Report

Merging #10676 will not alter performance

_{Comparing feature/replace-std-hashmap-with-rustc-hash (b58eb6d) with yj/enforce-fxhasher (a4648ff)}

Summary

✅ 12 untouched benchmarks