Uncomment one grammar test (#118361)

Author: sobolevn

Lib/test/test_grammar.py

@@ -164,7 +164,7 @@ def test_floats(self):
         x = 3.14
         x = 314.
         x = 0.314
-        # XXX x = 000.314
+        x = 000.314
         x = .314
         x = 3e14
         x = 3E14