Issue #23661: unittest.mock side_effects can now be exceptions again.

This was a regression vs Python 3.4. Patch from Ignacio Rossi
diff --git a/Misc/ACKS b/Misc/ACKS
index 8a007ea..9841059 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1581,3 +1581,4 @@
 Gennadiy Zlobin
 Doug Zongker
 Peter Åstrand
+Ignacio Rossi