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 f284a344c950cc88b7742b9bf527e77a3054612b..a60d9d3c2610a894bed8677d40c953d753172e6e 100644
--- a/src/code-stubs.h
+++ b/src/code-stubs.h
@@ -591,7 +591,7 @@ class FastNewClosureStub : public HydrogenCodeStub {
  private:
   STATIC_ASSERT(LANGUAGE_END == 3);
   class LanguageModeBits : public BitField<LanguageMode, 0, 2> {};
-  class FunctionKindBits : public BitField<FunctionKind, 2, 6> {};
+  class FunctionKindBits : public BitField<FunctionKind, 2, 7> {};
 
   DEFINE_CALL_INTERFACE_DESCRIPTOR(FastNewClosure);
   DEFINE_HYDROGEN_CODE_STUB(FastNewClosure, HydrogenCodeStub);