[Corn Flakes] C fix flaky test: ensure generate_random_even_number always returns even numbers

[Copilot]

[C] test_random_math_operations was persistently flaky because generate_random_even_number could intermittently return odd values. This change removes the intermittent odd-number path so the function consistently honors the even-number contract across ranges.

• Root-cause fix (C random even generator)

  • Removed the 5% corruption branch in c/src/random_math_operations.c that could increment an even value into an odd value.
  • Kept existing range normalization and parity-adjustment behavior intact.

• Test file alignment

  • Updated the stale test section comment in c/tests/test_random_math_operations.c to reflect that the even-number tests are no longer intentionally flaky.

int value = min + (rand() % (max - min + 1));

if (value % 2 != 0) {
    value += 1;
    if (value > max) {
        value -= 2;
    }
}

return value;