Teach the "old gate definition model" about SWAP.

[karlosz]

• Teach the chip reader how to deal with it.
• Adjust a test.

This just naively translates swap instructions directly when the object supports it.

[karlosz]

I accidentally messed up the last pull request implementing this but I've adjusted tests and taught the reader how to deal with SWAP now.

[karlosz]

Updated to have more sensible tests.