More Base64LineBreaker fuzzing

[dolmen]

• Fuzz Base64LineBreaker with various chunk sizes
• Check the count of written bytes reported by the base64 encoder

[wneessen]

Thanks for the PR @dolmen. Much appreciated. Code looks good to me and will be merged.
Out of curiosity, did you already give the new fuzzing code a longer run and was it able to find anything?

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 93.35%. Comparing base (24dad49) to head (12e837f).
Report is 2 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #443      +/-   ##
==========================================
- Coverage   94.34%   93.35%   -1.00%     
==========================================
  Files          30       30              
  Lines        3534     3534              
==========================================
- Hits         3334     3299      -35     
- Misses        147      187      +40     
+ Partials       53       48       -5     

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[dolmen]

I came here by looking for duplications of the lineBreaker code in encoding/pem.

See CL 653675 and CL 653676.