6711100: 64bit fastdebug server vm crashes with assert(_base == Int,"Not an Int")

Insert CastII nodes to narrow type of load_array_length() node

Reviewed-by: never, kvn
diff --git a/hotspot/src/share/vm/opto/memnode.hpp b/hotspot/src/share/vm/opto/memnode.hpp
index dff9dad..2b40a67 100644
--- a/hotspot/src/share/vm/opto/memnode.hpp
+++ b/hotspot/src/share/vm/opto/memnode.hpp
@@ -241,6 +241,7 @@
   virtual int Opcode() const;
   virtual const Type *Value( PhaseTransform *phase ) const;
   virtual Node *Identity( PhaseTransform *phase );
+  virtual Node *Ideal(PhaseGVN *phase, bool can_reshape);
 };
 
 //------------------------------LoadLNode--------------------------------------