In preparation for adding the zkEVM aggregation circuit. Mainly,
- Adds a `WitnessWrite` trait, a sub-trait of `Witness`, and move the write methods to it. `GeneratedValues` impls `WitnessWrite`, which lets generators like `DummyProofGenerator` access all our write methods like `set_proof_with_pis_target`. Also removes some duplication.
- Remove `set_cyclic_recursion_data_target` - now that dummy proof data is automatically populated, all that remains is populating `condition` and the cyclic proof + VK. I think it's easy enough for callers to do this; the steps are the same as with `conditionally_verify_proof`. This way there's no cyclic-recursion-specific API to learn about.
- Split `cyclic_recursion` into two variants, one which checks the current circuit or a dummy, and a more general one which checks the current circuit or some other circuit. We can use the latter to build a more efficient aggregation circuit, where we check another aggregation proof or an EVM proof, with no dummy proofs involved.
It was creating a new account with the hash of an empty storage trie, when really it should be a pointer to an empty storage trie. We can use 0 as this pointer since `@SEGMENT_TRIE_DATA[0] = 0 = @MPT_NODE_EMPTY`.
Also a couple tweaks that helped me debug, like moving the memory value range checks from the interpreter into `MemoryState`, so they're done in actual witness generation as well as interpreter tests.
* Add comments about number of columns used.
* Split modular operations across two rows.
* Fix test setup.
* Use constraint_transition() in common code.
* Ensure all inputs/outputs are on the first row.
* Fix constraint for single-row ops.
* Tidy up loop; make MODULAR_AUX_INPUT length reflect reality.
