UNION queries where the first query contains a nested query were parsed incorrectly.

h2/src/main/org/h2/command/Parser.java

@@ -951,10 +951,8 @@ public class Parser {
         String alias = null;
         if (readIf("(")) {
             if (isSelect()) {
-                int start = lastParseIndex;
                 Query query = parseSelectUnion();
                 read(")");
-                query = parseSelectUnionExtension(query, start, true);
                 ArrayList<Parameter> params = New.arrayList();
                 for (int i = 0; i < parameters.size(); i++) {
                     params.add(parameters.get(i));

h2/src/test/org/h2/test/test-1.2.txt

 --- special grammar and test cases ---------------------------------------------------------------------------------------------
+select 1, 2 from (select * from dual) union all select 3, 4 from dual;
+> 1 2
+> - -
+> 1 2
+> 3 4
+> rows: 2
+
+select 3 from (select * from dual) union all select 2 from dual;
+> 3
+> -
+> 2
+> 3
+> rows: 2
+
 create table a(x int, y int);
 > ok