Change types.pyi syntax that pytype can't parse. (#1157)

* Fix a few return types in stdlib/2/inspect.pyi.

* Rename _FrameRecord to _FrameInfo

* Correct some return types in itertools.pyi from Iterable to Iterator.

* Change types.pyi syntax that pytype can't parse.

stdlib/2/types.pyi

@@ -3,7 +3,7 @@
 
 from typing import (
     Any, Callable, Dict, Iterable, Iterator, List, Optional,
-    Tuple, TypeVar, Union, overload,
+    Tuple, Type, TypeVar, Union, overload,
 )
 
 _T = TypeVar('_T')
@@ -19,11 +19,12 @@ BooleanType = bool
 ComplexType = complex
 StringType = str
 UnicodeType = unicode
-StringTypes = (StringType, UnicodeType)
+StringTypes = ...  # type: Tuple[Type[StringType], Type[UnicodeType]]
 BufferType = buffer
 TupleType = tuple
 ListType = list
-DictType = DictionaryType = dict
+DictType = dict
+DictionaryType = dict
 
 class _Cell:
     cell_contents = ...  # type: Any