Add edge-case coverage for merge sort

[codingkiddo]

Summary

Add additional edge-case coverage for the MergeSort example.

Changes

• Add coverage for the smallest non-trivial recursive input with two elements in reverse order.
• Verify sorting with Integer.MIN_VALUE and Integer.MAX_VALUE.
• Add a deterministic 10,000-element randomized test and compare the result with Arrays.sort.

Testing

Ran:

mvn -f agents/reflection/pom.xml \
  -Dtest=ResultFromAgentTest \
  test

and:

mvn -f agents/reflection/pom.xml test

All tests pass.