Prohibit serializing with --harmony-scoping.

src/compiler.cc

Index: src/compiler.cc
diff --git a/src/compiler.cc b/src/compiler.cc
index 244ed8b7e34d8c0997a4fff4b634e56725ffeba5..b13cdd2614579488f343cc8a34cbf2e64cd03ab1 100644
--- a/src/compiler.cc
+++ b/src/compiler.cc
@@ -1221,7 +1221,10 @@ Handle<SharedFunctionInfo> Compiler::CompileScript(
     result = CompileToplevel(&info);
     if (extension == NULL && !result.is_null() && !result->dont_cache()) {
       compilation_cache->PutScript(source, context, result);
-      if (FLAG_serialize_toplevel &&
+      // TODO(yangguo): Issue 3628
+      // With block scoping, top-level variables may resolve to a global,
+      // context, which makes the code context-dependent.
+      if (FLAG_serialize_toplevel && !FLAG_harmony_scoping &&
           compile_options == ScriptCompiler::kProduceCodeCache) {
         HistogramTimerScope histogram_timer(
             isolate->counters()->compile_serialize());