Refactor sending of DataRow messages in replication protocol

Some routines open-coded the construction of DataRow messages.  Use
TupOutputState struct and associated functions instead, which was
already done in some places.

SendTimeLineHistory() is a bit more complicated and isn't converted by
this.

Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/7e4fdbdc-699c-4cd0-115d-fb78a957fc22@enterprisedb.com

src/backend/access/common/printsimple.c

@@ -121,6 +121,17 @@ printsimple(TupleTableSlot *slot, DestReceiver *self)
 				}
 				break;
 
+			case OIDOID:
+				{
+					Oid			num = ObjectIdGetDatum(value);
+					char		str[10];	/* 10 digits */
+					int			len;
+
+					len = pg_ultoa_n(num, str);
+					pq_sendcountedtext(&buf, str, len, false);
+				}
+				break;
+
 			default:
 				elog(ERROR, "unsupported type OID: %u", attr->atttypid);
 		}