Remove support for partial receipts
Executor v1 supports receiving a synthetic transaction's receipt in multiple parts, as in one part from the originating partition, and another part from the directory network. Remove this support and instead always require a complete receipt when processing a synthetic transaction.
Support for partial receipts can lower latency but adds considerable complexity to the synthetic message processing code. And regardless, partial receipts are not used on 1.0.0 due to unexplained performance issues (AC-2438). Additionally, supporting partial receipts requires indexing pending synthetic transactions against the anchor they are waiting for, which adds complexity to snapshots and BPT calculations.
Edited by Ethan Reesor