Fix timeti test nightly/3.7

IPython/core/magics/execution.py

@@ -109,7 +109,7 class TimeitResult(object):
         unic = self.__str__()
         p.text(u'<TimeitResult : '+unic+u'>')
 
-
+_pass = ast.Pass()
 
 class TimeitTemplateFiller(ast.NodeTransformer):
     """Fill in the AST template for timing execution.

IPython/core/tests/test_magic.py

@@ -564,7 +564,13 def test_timeit_shlex():
 
 def test_timeit_arguments():
     "Test valid timeit arguments, should not cause SyntaxError (GH #1269)"
-    _ip.magic("timeit ('#')")
+    if sys.version_info < (3,7):
+        _ip.magic("timeit ('#')")
+    else:
+        # 3.7 optimize no-op statement like above out, and complain there is
+        # nothing in the for loop.
+        _ip.magic("timeit a=('#')")
+
 
 
 def test_timeit_special_syntax():