Refactor CLUSTER and REINDEX grammar to use DefElem for option lists

This changes CLUSTER and REINDEX so as a parenthesized grammar becomes
possible for options, while unifying the grammar parsing rules for
option lists with the existing ones.

This is a follow-up of the work done in 873ea9e for VACUUM, ANALYZE and
EXPLAIN.  This benefits REINDEX for a potential backend-side filtering
for collatable-sensitive indexes and TABLESPACE, while CLUSTER would
benefit from the latter.

Author: Alexey Kondratov, Justin Pryzby
Discussion: https://postgr.es/m/8a8f5f73-00d3-55f8-7583-1375ca8f6a91@postgrespro.ru

src/include/commands/cluster.h

@@ -14,11 +14,19 @@
 #define CLUSTER_H
 
 #include "nodes/parsenodes.h"
+#include "parser/parse_node.h"
 #include "storage/lock.h"
 #include "utils/relcache.h"
 
 
-extern void cluster(ClusterStmt *stmt, bool isTopLevel);
+/* options for CLUSTER */
+typedef enum ClusterOption
+{
+	CLUOPT_RECHECK = 1 << 0,	/* recheck relation state */
+	CLUOPT_VERBOSE = 1 << 1		/* print progress info */
+} ClusterOption;
+
+extern void cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel);
 extern void cluster_rel(Oid tableOid, Oid indexOid, int options);
 extern void check_index_is_clusterable(Relation OldHeap, Oid indexOid,
 									   bool recheck, LOCKMODE lockmode);

src/include/commands/defrem.h

@@ -34,6 +34,7 @@ extern ObjectAddress DefineIndex(Oid relationId,
 								 bool check_not_in_use,
 								 bool skip_build,
 								 bool quiet);
+extern int	ReindexParseOptions(ParseState *pstate, ReindexStmt *stmt);
 extern void ReindexIndex(RangeVar *indexRelation, int options, bool isTopLevel);
 extern Oid	ReindexTable(RangeVar *relation, int options, bool isTopLevel);
 extern void ReindexMultipleTables(const char *objectName, ReindexObjectType objectKind,