Remove duplicate initialization

This appears to be a merge mistake in 96ef3237bf.  We could put it
back the way it was before JSON_TABLE and it'd be two lines shorter, but
it's likely that JSON_TABLE will be back and will prefer things this
way.  It makes no other difference in practice.

Backpatch to 15.

Reported by Ranier Vilela
Discussion: https://postgr.es/m/CAEudQAr4nOcNQskC4oBEZN4S+4heJ=1ch_ZKOxU+_Ef-FQSf-g@mail.gmail.com

src/backend/parser/parse_relation.c

@@ -2017,7 +2017,7 @@ addRangeTableEntryForTableFunc(ParseState *pstate,
 							   bool inFromCl)
 {
 	RangeTblEntry *rte = makeNode(RangeTblEntry);
-	char	   *refname = alias ? alias->aliasname : pstrdup("xmltable");
+	char	   *refname;
 	Alias	   *eref;
 	int			numaliases;
 
@@ -2035,7 +2035,7 @@ addRangeTableEntryForTableFunc(ParseState *pstate,
 	Assert(list_length(tf->coltypmods) == list_length(tf->colnames));
 	Assert(list_length(tf->colcollations) == list_length(tf->colnames));
 
-	refname = alias ? alias->aliasname :  pstrdup("xmltable");
+	refname = alias ? alias->aliasname : pstrdup("xmltable");
 
 	rte->rtekind = RTE_TABLEFUNC;
 	rte->relid = InvalidOid;