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 365012cdc57689019c337e35e0b9dee5e04c2085..058bd89c01d30ee3b70974660e93ed3e44fac9de 100644
--- a/src/x64/full-codegen-x64.cc
+++ b/src/x64/full-codegen-x64.cc
@@ -742,9 +742,8 @@ 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.
 }