test: remove leftover useless code in BitArrayTest

[vlakoff]

As raised in this comment, the following lines are unnecessary and can safely be deleted:

if ($actual !== $expected) {
    $array->getNextSet($query);
}

• These lines do not exist in the source test logic.
• They serve no purpose and appear to be leftover code.
• Removing them improves test clarity and avoids confusion.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 70.51%. Comparing base (741e712) to head (08f0c76).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##               main     #210   +/-   ##
=========================================
  Coverage     70.51%   70.51%           
  Complexity      993      993           
=========================================
  Files            49       49           
  Lines          3174     3174           
=========================================
  Hits           2238     2238           
  Misses          936      936           

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