Cover zero operands, power-of-2 fast path, negative operands,
balanced multi-limb pairs with a shared Fibonacci factor, highly
unbalanced pairs (to exercise the Euclidean fallback), and
Fibonacci neighbors (always coprime). Declare a test dependency
on mruby-numeric-ext since Integer#gcd is defined there.
Co-authored-by: Claude <noreply@anthropic.com>
Users can now switch to their own implementation of GEM.
However, we do not guarantee that this will not be a problem in the current situation.
This may need to be improved in the future.