Expand JIT groupby test suite (#13813)

This PR reorganizes and expands the test suite for groupby apply functions using the JIT engine to include nan cases and cases where the groups are larger than a single thread block.

Authors:
  - https://github.com/brandon-b-miller

Approvers:
  - Bradley Dice (https://github.com/bdice)
  - Vyas Ramasubramani (https://github.com/vyasr)

URL: #13813