Encode/decode testing for Argument types

[t-h-p]

This Pull Request fixes/closes #4240.

It changes the following:

• Adds tests for encode/decode functionality for all argument types.
• Changes formatting for reads and writes of (VaryingOperand,i32).

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 52.96%. Comparing base (6ddc2b4) to head (3f15298). Report is 430 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4284      +/-   ##
==========================================
+ Coverage   47.24%   52.96%   +5.72%     
==========================================
  Files         476      494      +18     
  Lines       46892    51526    +4634     
==========================================
+ Hits        22154    27291    +5137     
+ Misses      24738    24235     -503     

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[t-h-p]

I made the requested changes and formatted it, this should pass the checks.

[HalidOdat]

A lot of rust tests seem to be failing, have you checked why?

[t-h-p]

I made the most recent commit without running the full test suite or clippy, my mistake. I also found the changes that were causing most of the issues. (u32,VaryingOperand) and (u32, VaryingOperand, VaryingOperand) both break a lot of tests when formatting is added, instead of using write_u32 for all variants. Now I am trying to figure out the problem.