Terminate generator in test to avoid having its exception state hang around,...

Terminate generator in test to avoid having its exception state hang around, which leads to exception leaks in Py3.3 for the pure Python comparison test.

tests/run/generators_py.py

@@ -164,6 +164,9 @@ def check_yield_in_except():
     True
     True
     True
+    >>> next(g)
+    Traceback (most recent call last):
+    StopIteration
     """
     try:
         yield