Improve internal logical replication error for missing equality strategy

This "shouldn't happen", except right now it can with a temporal gist
index (to be fixed soon), because of missing gist support in
get_equal_strategy_number().  But right now, the error is not caught
right away, but instead you get the subsequent error about a "missing
operator 0".  This makes the error more accurate.

Author: Paul Jungwirth <[email protected]>
Discussion: https://www.postgresql.org/message-id/flat/CA+renyUApHgSZF9-nd-a0+OPGharLQLO=mDHcY4_qQ0+noCUVg@mail.gmail.com

Author: petere

src/backend/executor/execReplication.c

@@ -134,6 +134,8 @@ build_replindex_scan_key(ScanKey skey, Relation rel, Relation idxrel,
 		optype = get_opclass_input_type(opclass->values[index_attoff]);
 		opfamily = get_opclass_family(opclass->values[index_attoff]);
 		eq_strategy = get_equal_strategy_number(opclass->values[index_attoff]);
+		if (!eq_strategy)
+			elog(ERROR, "missing equal strategy for opclass %u", opclass->values[index_attoff]);
 
 		operator = get_opfamily_member(opfamily, optype,
 									   optype,