feat: fuzzing json inputs for report merging

[yashugarg]

I learned about importing .proto files and found exciting JSON functions so I tried them out in fuzzing MergeReports.

[yashugarg]

@terriko, these new tests don't yield any interesting results at the moment (It's mostly just MissingFieldError). I am trying to figure out how to force protobuf to provide non-empty strings in message fields.
Could you keep it running on the cloud VM, if possible, to see what we get after getting past the MissingFieldError?

[codecov-commenter]

Codecov Report

Merging #1888 (03f13e0) into main (661c796) will increase coverage by 9.54%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #1888      +/-   ##
==========================================
+ Coverage   78.93%   88.48%   +9.54%     
==========================================
  Files         316      316              
  Lines        7269     7269              
  Branches     1184     1184              
==========================================
+ Hits         5738     6432     +694     
+ Misses       1281      581     -700     
- Partials      250      256       +6     

Flag	Coverage Δ
longtests	78.95% <ø> (+0.01%)	⬆️
win-longtests	87.46% <ø> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
cve_bin_tool/version_scanner.py	86.71% <0.00%> (+0.69%)	⬆️
cve_bin_tool/merge.py	80.32% <0.00%> (+0.81%)	⬆️
cve_bin_tool/helper_script.py	86.23% <0.00%> (+0.91%)	⬆️
cve_bin_tool/parsers/java.py	75.00% <0.00%> (+1.47%)	⬆️
test/test_checkers.py	95.16% <0.00%> (+1.61%)	⬆️
test/test_extractor.py	95.67% <0.00%> (+2.16%)	⬆️
cve_bin_tool/output_engine/util.py	88.15% <0.00%> (+2.63%)	⬆️
cve_bin_tool/output_engine/__init__.py	72.61% <0.00%> (+2.77%)	⬆️
cve_bin_tool/checkers/glibc.py	100.00% <0.00%> (+4.16%)	⬆️
cve_bin_tool/version.py	100.00% <0.00%> (+5.88%)	⬆️
... and 18 more

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[terriko]

I don't know offhand how to make protobuf not do empty strings (though there's probably a way) but you can do the check in the python code on data or just ignore MissingFieldError the way we ignore SystemExit.

Anyhow, I'll merge this so you can iterate. I'm not going to have time to get a cloud instance up and rolling before we meet tomorrow, but hopefully after!