Fix bug in the fast compiler's object literal code...

src/x64/fast-codegen-x64.cc

Index: src/x64/fast-codegen-x64.cc
===================================================================
--- src/x64/fast-codegen-x64.cc	(revision 3369)
+++ src/x64/fast-codegen-x64.cc	(working copy)
@@ -666,8 +666,9 @@
     __ CallRuntime(Runtime::kCloneLiteralBoilerplate, 1);
   }
 
-  // If result_saved == true: the result is saved on top of the stack.
-  // If result_saved == false: the result is not on the stack, just in rax.
+  // If result_saved == true: The result is saved on top of the
+  //  stack and in rax.
+  // If result_saved == false: The result not on the stack, just in rax.
   bool result_saved = false;
 
   for (int i = 0; i < expr->properties()->length(); i++) {
@@ -692,6 +693,7 @@
           Handle<Code> ic(Builtins::builtin(Builtins::StoreIC_Initialize));
           __ call(ic, RelocInfo::CODE_TARGET);
           // StoreIC leaves the receiver on the stack.
+          __ movq(rax, Operand(rsp, 0));  // Restore result back into rax.
           break;
         }
         // fall through