Removed static type inference and add a dynamic test for string addition.

src/x64/virtual-frame-x64.h

 // Copyright 2009 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 360 matching lines @@
   void EmitPop(Register reg);
   void EmitPop(const Operand& operand);
 
   // Push an element on top of the expression stack and emit a
   // corresponding push instruction.
   void EmitPush(Register reg);
   void EmitPush(const Operand& operand);
   void EmitPush(Immediate immediate);
 
   // Push an element on the virtual frame.
-  void Push(Register reg, StaticType static_type = StaticType());
+  void Push(Register reg);
   void Push(Handle<Object> value);
   void Push(Smi* value) { Push(Handle<Object>(value)); }
 
   // Pushing a result invalidates it (its contents become owned by the
   // frame).
   void Push(Result* result) {
     if (result->is_register()) {
-      Push(result->reg(), result->static_type());
+      Push(result->reg());
     } else {
       ASSERT(result->is_constant());
       Push(result->handle());
     }
     result->Unuse();
   }
 
   // Nip removes zero or more elements from immediately below the top
   // of the frame, leaving the previous top-of-frame value on top of
   // the frame.  Nip(k) is equivalent to x = Pop(), Drop(k), Push(x).
@@ skipping 144 matching lines @@
 
   // Classes that need raw access to the elements_ array.
   friend class DeferredCode;
   friend class JumpTarget;
 };
 
 
 } }  // namespace v8::internal
 
 #endif  // V8_X64_VIRTUAL_FRAME_X64_H_