Delete deprecated starboard header files

[madhurajayaraman]

b/362374622

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 57.56%. Comparing base (eb3f507) to head (4fa8d7f).
Report is 9 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #4106      +/-   ##
==========================================
- Coverage   57.57%   57.56%   -0.02%     
==========================================
  Files        1746     1745       -1     
  Lines       86403    86403              
==========================================
- Hits        49747    49737      -10     
- Misses      36656    36666      +10     

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[kaidokert]

Mostly just empty line cleanup nits, and a few empty #ifdef STARBOARDs to get rid of

[kaidokert]

LGTM