Postpone the argument type optimizations until the types are stable.

lib/compiler/implementation/ssa/nodes.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 interface HVisitor<R> {
   R visitAdd(HAdd node);
   R visitBitAnd(HBitAnd node);
   R visitBitNot(HBitNot node);
   R visitBitOr(HBitOr node);
   R visitBitXor(HBitXor node);
@@ skipping 917 matching lines @@
         oldInputUsers[i] = oldInputUsers[oldInput.usedBy.length - 1];
         oldInputUsers.length = oldInputUsers.length - 1;
       }
     }
   }
 
   bool isConstant() => false;
   bool isConstantBoolean() => false;
   bool isConstantNull() => false;
   bool isConstantNumber() => false;
+  bool isConstantInteger() => false;
   bool isConstantString() => false;
   bool isConstantList() => false;
   bool isConstantMap() => false;
   bool isConstantFalse() => false;
   bool isConstantTrue() => false;
-  bool isConstantInteger() => false;
 
   bool isValid() {
     HValidator validator = new HValidator();
     validator.currentBlock = block;
     validator.visitInstruction(this);
     return validator.isValid;
   }
 
   /**
    * The code for computing a bailout environment, and the code
@@ skipping 1627 matching lines @@
   HBasicBlock get start() => expression.start;
   HBasicBlock get end() {
     // We don't create a switch block if there are no cases.
     assert(!statements.isEmpty());
     return statements.last().end;
   }
 
   bool accept(HStatementInformationVisitor visitor) =>
       visitor.visitSwitchInfo(this);
 }