faa24441ec policy: Remove promiscuousmempoolflags (MarcoFalke)
Pull request description:
It seems odd to clutter validation code with features that can only ever be used for testing (testnet or regtest). Removing that test-only code makes the mempool logic less painful to understand and easier to reason about when changed or refactored in the future.
Tree-SHA512: 3b897aa9604ac8d82ebe9573c6efd468c93ddaa08d378ebc902e247b7aa6c68fcde71e5b449c08f17a067146cdc66dc50a67ce06d07607c27e5189a49c3fba3f