Add check for sys crate publish; Script cleanup

[justsmth]

Description of changes:

• Add check to sys-crate publishing script to verify expected prefix.
• Fix how generation scripts check for macOS.
• Remove generation script expectation that we're on main.
• Other cleanup in generation scripts.

Testing:

Tested on macos and linux hosts

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license and the ISC license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.82%. Comparing base (8a6facc) to head (f63b039).

Additional details and impacted files

@@           Coverage Diff           @@
##             main     #351   +/-   ##
=======================================
  Coverage   95.82%   95.82%           
=======================================
  Files          60       60           
  Lines        7865     7865           
=======================================
  Hits         7537     7537           
  Misses        328      328           

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