UT random failure

[shargon]

Describe the bug
UT fail randomly, I think that it's because we Commit the snapshot in order to validate some tx, balance etc.

        [TestMethod]
        public void TestValidTransaction()
        {
            using var snapshot = TestBlockchain.TheNeoSystem.GetSnapshot();
            var walletA = TestUtils.GenerateTestWallet("123");
            var acc = walletA.CreateAccount();

            // Fake balance

            var key = new KeyBuilder(NativeContract.GAS.Id, 20).Add(acc.ScriptHash);
            var entry = snapshot.GetAndChange(key, () => new StorageItem(new AccountState()));
            entry.GetInteroperable<AccountState>().Balance = 100_000_000 * NativeContract.GAS.Factor;
            snapshot.Commit();

            // Make transaction

            var tx = CreateValidTx(snapshot, walletA, acc.ScriptHash, 0);

            senderProbe.Send(system.Blockchain, tx);
            senderProbe.ExpectMsg<Blockchain.RelayResult>(p => p.Result == VerifyResult.Succeed);

            senderProbe.Send(system.Blockchain, tx);
            senderProbe.ExpectMsg<Blockchain.RelayResult>(p => p.Result == VerifyResult.AlreadyInPool);
        }

To Reproduce
Steps to reproduce the behavior:

1. Choose Neo.UnitTests.Ledger and Neo.UnitTests.SmartContract
2. Run until failure

Expected behavior
UT's should work .

Screenshots

[Jim8y]

we need mock snapshot