Add assert to make sure that function refers to compiled code in handles.cc

src/compiler.h

Index: src/compiler.h
diff --git a/src/compiler.h b/src/compiler.h
index d8eb3a68f408537ca200717c8bb5f5e83b5268cc..4e4e61300d819e0395f95238a549d073a1dde61a 100644
--- a/src/compiler.h
+++ b/src/compiler.h
@@ -132,6 +132,10 @@ class LazyFunctionCompilationInfo: public CompilationInfo {
     return Handle<SharedFunctionInfo>(closure_->shared());
   }
 
+  virtual Handle<JSFunction> closure() const {
+    return closure_;
+  }
+
   virtual int loop_nesting() const { return loop_nesting_; }
 
   virtual bool has_global_object() const {