ISPN-2875 Intermittent test failure: org.infinispan.statetransfer.DistNonTxOperationsDuringStateTransferTest

Delaying execution of Transport.invokeRemotely(CacheTopologyControlCommand) on coordinator is usually enough
to delay the start of rebalance on the joiner in most cases but not in the rare case when the joiner receives a non-null
pending CH right in the initial topology returned to it from the join call. This was causing the assert to fail. A more manageable
way of delaying start of rebalance is to override the RebalancePolicy rather than the Transport. This approach ensures (at least in this test scenario) that the initial topology has a null pending CH.
ISPN-2847 No longer needed to mark transactions that are from state transfer in StateConsumerImpl

This code was moved to TxInterceptor.enlistWriteAndInvokeNext for ISPN-2847 and is superfluous here. Was left behind by mistake.