Fix Foreign key fuzzer to ignore rows affected

[GuptaManan100]

Description

After noticing the problem #15826 and running into the issues described in #15779 (comment) and #15779 (comment), the Vitess maintainers have decided not to fix the issue, and instead let the rows affected fields for Vitess and MySQL differ. The reasoning is that all the users of MySQL with foreign keys, should already be accustomed to having the rows affected being different from the total number of row deletions (because MySQL doesn't count the rows deleted via CASCADEs as they happen at the InnoDB level). Moreover, it will take significant code changes and performance penalty to match the MySQL behaviour. We would have to do multiple SELECT queries to find the number of qualifying rows for a DML operation upfront. This however, doesn't feel like the prudent way forward. Instead we are fixing the fuzzer to ignore the rows affected fields while testing and adding a test case for the queries listed in the bug to ensure everything else works.

Related Issue(s)

• Fixes Bug Report: Incorrect rows affected in foreign keys enabled keyspace #15826

Checklist

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 68.42%. Comparing base (f118ba2) to head (18aa3a3).
Report is 58 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #15841      +/-   ##
==========================================
+ Coverage   68.40%   68.42%   +0.01%     
==========================================
  Files        1556     1559       +3     
  Lines      195121   196511    +1390     
==========================================
+ Hits       133479   134460     +981     
- Misses      61642    62051     +409     

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[frouioui]

This is a nice refactoring, looks good to me