Remove no longer necessary val_unrolled_reduce workaround

[dennisYatunin]

This PR removes the method for unrolled_reduce that specialized on a Val as its input (instead of specializing on an iterator), along with the underlying definition of val_unrolled_reduce.

This workaround was previously required to avoid long compilation times in three of the CPU tests for the non-orographic gravity wave parametrization in ClimaAtmos. Since CliMA/ClimaAtmos.jl#3313 has isolated the specific aspect of val_unrolled_reduce that was allowing us to avoid long compilation times, this non-standard implementation of unrolled_reduce is no longer necessary.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 60.52%. Comparing base (5e77b08) to head (1cc30ad).
Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #20      +/-   ##
==========================================
+ Coverage   59.19%   60.52%   +1.33%     
==========================================
  Files           7        7              
  Lines         272      266       -6     
==========================================
  Hits          161      161              
+ Misses        111      105       -6     

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