Make functions on the built-in object non-writable.

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 dd35053a654ff44e468e1db5d3053cc85361c07b..3e3afc29823f769cfaae3fd17b21c359d27429d0 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -741,9 +741,8 @@ void FullCodeGenerator::DeclareGlobals(Handle<FixedArray> pairs) {
   // Call the runtime to declare the globals.
   __ push(rsi);  // The context is the first argument.
   __ Push(pairs);
-  __ Push(Smi::FromInt(is_eval() ? 1 : 0));
-  __ Push(Smi::FromInt(strict_mode_flag()));
-  __ CallRuntime(Runtime::kDeclareGlobals, 4);
+  __ Push(Smi::FromInt(DeclareGlobalsFlags()));
+  __ CallRuntime(Runtime::kDeclareGlobals, 3);
   // Return value is ignored.
 }