Fix bug in assignment of next jsquery item offset.

Output buffer could be reallocated after next item is filled.  So, we need
to make sure that we calculate pointer inside the buffer after item is filled.

Author: Alexander Korotkov

expected/jsquery.out

@@ -1656,6 +1656,12 @@ select '{"a":{"aa":1}, "b":{"aa":1, "bb":2}}' @@ '*: (not $ is object or $.aa is
  t
 (1 row)
 
+SELECT 'test.# IN (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64)'::jsquery;
+                                                                                                                               jsquery                                                                                                                               
+---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
+ "test".# IN (1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64)
+(1 row)
+
 select '[]' @@ '(@# > 0 and #: = 16)'::jsquery;
  ?column? 
 ----------

jsquery_io.c

@@ -135,7 +135,10 @@ flattenJsQueryParseItem(StringInfo buf, JsQueryParseItem *item, bool onlyCurrent
 	}
 
 	if (item->next)
-		*(int32*)(buf->data + next) = flattenJsQueryParseItem(buf, item->next, onlyCurrentInPath);
+	{
+		chld = flattenJsQueryParseItem(buf, item->next, onlyCurrentInPath);
+		*(int32*)(buf->data + next) = chld;
+	}
 
 	return  pos;
 }

sql/jsquery.sql

@@ -331,6 +331,7 @@ select '{"a":{"aa":1}, "b":{"aa":1, "bb":2}}' @@ '%:.aa is numeric'::jsquery;
 select '{"a":{"aa":1}, "b":{"aa":true, "bb":2}}' @@ '%:.aa is numeric'::jsquery;
 select '{"a":{"aa":1}, "b":{"aa":1, "bb":2}, "aa":16}' @@ '*: (not $ is object or $.aa is numeric)'::jsquery;
 select '{"a":{"aa":1}, "b":{"aa":1, "bb":2}}' @@ '*: (not $ is object or $.aa is numeric or % is object)'::jsquery;
+SELECT 'test.# IN (1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64)'::jsquery;
 
 select '[]' @@ '(@# > 0 and #: = 16)'::jsquery;
 select '[16]' @@ '(@# > 0 and #: = 16)'::jsquery;