During new transaction verification if there's an on-chain conflicting
transaction, we should check the signers of this conflicting transaction.
If the signers intersect with signers of the incoming transaction, then
the conflict is treated as valid and verification for new incoming
transaction should fail. Otherwise, the conflict is treated as the
malicious attack attempt and will not be taken into account;
verification for the new incoming transaction should continue.
This commint implements the scheme described at
https://github.com/neo-project/neo/pull/2818#issuecomment-1632972055,
thanks to @shargon for digging.
Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
133082ed58