Remove some unnecessary binding initialization checks.

src/x64/full-codegen-x64.cc

Index: src/x64/full-codegen-x64.cc
diff --git a/src/x64/full-codegen-x64.cc b/src/x64/full-codegen-x64.cc
index 8d4792ee5d17efd78d2a771ba86b24d21d3b7ccd..d1565cca3567873f451f87ed7eec912a77a2d707 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -687,8 +687,8 @@ void FullCodeGenerator::EmitDeclaration(VariableProxy* proxy,
   // need to "declare" it at runtime to make sure it actually exists in the
   // local context.
   Variable* variable = proxy->var();
-  bool binding_needs_init =
-      mode == CONST || mode == CONST_HARMONY || mode == LET;
+  bool binding_needs_init = (function == NULL) &&
+      (mode == CONST || mode == CONST_HARMONY || mode == LET);
   switch (variable->location()) {
     case Variable::UNALLOCATED:
       ++(*global_count);