new classes: assert that constructors are not callable and rewrite 'return;'

src/code-stubs.h

Index: src/code-stubs.h
diff --git a/src/code-stubs.h b/src/code-stubs.h
index 3e6ea44ea99a6de8791e5ed8f30eb95ea3751db9..c2553c6e0806ed2b13cd23963865abf74c2c0103 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -595,7 +595,7 @@ class FastNewClosureStub : public HydrogenCodeStub {
  private:
   STATIC_ASSERT(LANGUAGE_END == 2);
   class LanguageModeBits : public BitField<LanguageMode, 0, 1> {};
-  class FunctionKindBits : public BitField<FunctionKind, 1, 4> {};
+  class FunctionKindBits : public BitField<FunctionKind, 1, 6> {};
 
   DEFINE_CALL_INTERFACE_DESCRIPTOR(FastNewClosure);
   DEFINE_HYDROGEN_CODE_STUB(FastNewClosure, HydrogenCodeStub);