Add support for V128 to wasmi_wast crate

[Robbepop]

This allows consuming Wasm simd proposal Wast tests.

[codecov]

Codecov Report

Attention: Patch coverage is 20.83333% with 38 lines in your changes missing coverage. Please review.

Project coverage is 67.33%. Comparing base (33ff214) to head (16ee09e).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
crates/wast/src/lib.rs	20.83%	38 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1419      +/-   ##
==========================================
- Coverage   67.49%   67.33%   -0.17%     
==========================================
  Files         159      159              
  Lines       15115    15157      +42     
==========================================
+ Hits        10202    10206       +4     
- Misses       4913     4951      +38     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.