Eliminate write barrier for global stores at compile time if value stored is a smi.

src/x64/lithium-codegen-x64.h

Index: src/x64/lithium-codegen-x64.h
===================================================================
--- src/x64/lithium-codegen-x64.h	(revision 9605)
+++ src/x64/lithium-codegen-x64.h	(working copy)
@@ -260,8 +260,10 @@
   // Emits optimized code for typeof x == "y".  Modifies input register.
   // Returns the condition on which a final split to
   // true and false label should be made, to optimize fallthrough.
-  Condition EmitTypeofIs(Label* true_label, Label* false_label,
-                         Register input, Handle<String> type_name);
+  Condition EmitTypeofIs(Label* true_label,
+                         Label* false_label,
+                         Register input,
+                         Handle<String> type_name);
 
   // Emits optimized code for %_IsObject(x).  Preserves input register.
   // Returns the condition on which a final split to