Remove dead code from the VM.

[lemmih]

Issue summary

The VM structure contains a bunch of dead code from before the switch to the FVM. It should be removed together with as many of the lifetime variables as possible:

forest/vm/interpreter/src/vm.rs

Lines 94 to 117 in df52270

	pub struct VM<
	'db,
	'r,
	DB: BlockStore + 'static,
	R,
	C: CircSupplyCalc,
	LB,
	V = FullVerifier,
	P = DefaultNetworkParams,
	> {
	_state: Rc<RefCell<StateTree<'db, DB>>>,
	_store: &'db DB,
	_epoch: ChainEpoch,
	_rand: &'r R,
	_base_fee: BigInt,
	registered_actors: HashSet<Cid>,
	_network_version: NetworkVersion,
	_circ_supply_calc: C,
	fvm_executor: fvm::executor::DefaultExecutor<ForestKernel<DB>>,
	_lb_state: &'r LB,
	verifier: PhantomData<V>,
	params: PhantomData<P>,
	heights: Heights,
	}

Other information and links