Remove the Query structure from the executor's API. This allows us to stop

storing mostly-redundant Query trees in prepared statements, portals, etc.
To replace Query, a new node type called PlannedStmt is inserted by the
planner at the top of a completed plan tree; this carries just the fields of
Query that are still needed at runtime.  The statement lists kept in portals
etc. now consist of intermixed PlannedStmt and bare utility-statement nodes
--- no Query.  This incidentally allows us to remove some fields from Query
and Plan nodes that shouldn't have been there in the first place.

Still to do: simplify the execution-time range table; at the moment the
range table passed to the executor still contains Query trees for subqueries.

initdb forced due to change of stored rules.

src/include/commands/portalcmds.h

@@ -7,13 +7,14 @@
  * Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/include/commands/portalcmds.h,v 1.20 2007/01/05 22:19:53 momjian Exp $
+ * $PostgreSQL: pgsql/src/include/commands/portalcmds.h,v 1.21 2007/02/20 17:32:17 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
 #ifndef PORTALCMDS_H
 #define PORTALCMDS_H
 
+#include "nodes/parsenodes.h"
 #include "utils/portal.h"