fix test_py3kwarns
The fact that this was failing and went unnoticed so long seems like a good argument for being able to enable and disble py3kwarnings through Python.
diff --git a/Lib/plat-mac/argvemulator.py b/Lib/plat-mac/argvemulator.py
index 1bc5da6..3dfc9f8 100644
--- a/Lib/plat-mac/argvemulator.py
+++ b/Lib/plat-mac/argvemulator.py
@@ -3,7 +3,7 @@
"""
from warnings import warnpy3k
-warnpy3k("In 3.x, the argvemulator module is removed.")
+warnpy3k("In 3.x, the argvemulator module is removed.", stacklevel=2)
import sys
import traceback