[3.7] bpo-36983: Fix typing.__all__ and add test for exported names (GH-13456) (GH-13662)



https://bugs.python.org/issue36983

Fixes issue 36983
diff --git a/Lib/typing.py b/Lib/typing.py
index 8cf0d00..9851cb4 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -36,6 +36,7 @@
     'Any',
     'Callable',
     'ClassVar',
+    'ForwardRef',
     'Generic',
     'Optional',
     'Tuple',
@@ -79,11 +80,13 @@
     'SupportsRound',
 
     # Concrete collection types.
+    'ChainMap',
     'Counter',
     'Deque',
     'Dict',
     'DefaultDict',
     'List',
+    'OrderedDict',
     'Set',
     'FrozenSet',
     'NamedTuple',  # Not really a type.