Multi output primitives

[awni]

Proposed changes

Enables multi output primitives.

Also added divmod as a multi-output primitive. Not so much because we need it, but I wanted to test the multi-output functionality.

TODOs

• [x] Add an actual multi output primitive, so far everything is single output
• [ ] Deal with TODOs in the code
• [x] Fix simplify
• [x] Run a few benchmarks and training scripts to see the damage.