The 'from' and 'to' methods on StateTransitions are reader methods and
shouldn't have inadvertent side effects on state.
It is safe to remove the check in 'from' because account existence is
implicitly checked by the nonce and balance checks. If the account has
non-zero balance or nonce, it must exist. Even if the sender account has
nonce zero at the start of the state transition or no balance, the nonce
is incremented before execution and the account will be created at that
time.
It is safe to remove the check in 'to' because the EVM creates the
account if necessary.
Fixes#15119
3caf16b15f