Clean up NFR test result formatting

[sjberman]

Problem: Some results files added extra newlines, causing our formatter to fail. Also, error log files were way too large for feasible parsing.

Solution: Remove extra newlines, and only include error logs instead of full log files.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 89.21%. Comparing base (81d4142) to head (81eef15).
Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2505   +/-   ##
=======================================
  Coverage   89.21%   89.21%           
=======================================
  Files         100      100           
  Lines        7539     7539           
  Branches       50       50           
=======================================
  Hits         6726     6726           
  Misses        756      756           
  Partials       57       57           

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