Create 2 transaction tests that consume and output notes

[phklive]

For now we have tests that verify the correct functionality of txs when:

• A test of a transaction which consumes a single note.
• A test of a transaction which produces a single note.

To be able to have a more thorough coverage we would need to implement the following tests:

• A test of a transaction which consumes a note and produces a note.
• A test of a transaction which consumes more than 1 note and produces more than 1 note.

This was also discussed in the following PR: #438

Goal of this issue:

Create 2 tests:

• Test consuming 1 and producing 1 note
• Test consuming 2 and producing 2 notes

[bobbinth]

I think we can consolidate these with some of the current tests we have. Specifically, we can have the following tests:

1. Create a SWAP note from basic wallet. This could replace the current prove_send_asset_via_wallet and prove_swap_script.
2. Consume a SWAP note into the basic wallet. This would be the test for a transaction consuming and producing a note.
3. Consume the P2ID note generated in step 2. This could replace prove_p2id_script and prove_receive_asset_via_wallet.

So, this would fulfill the "consuming 1 and producing 1 note" test and reduce the total number of "prove" tests by 3.

For "consuming 2 and producing 2 notes" test we could do something similar to the above, but would only test execution (not proving).