perf: hoist loop variable in minimizer to improve partitioning speed

[Tugamer89]

What: Hoisted the transitions == null check outside the inner loop in Minimizer.java's splitGroup method and used Arrays.fill for initialization when true.

Why: To improve performance during Moore's partition refinement algorithm by avoiding repeated, redundant conditional checks on invariant data within the inner loop structure and leveraging faster native array assignments.

Impact: Reduces redundant evaluations and branching during DFA minimization, slightly improving CPU cache locality and speeding up the inner execution cycle of partitioning logic.

Measurement: Checked via JUnit (mvn test) and formatting via mvn spotless:apply to verify exact functional parity without regressions.

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PR created automatically by Jules for task 3907266816387166818 started by @Tugamer89

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud