- Fix segfault with invalid coding.
- SF Bug #772896, unknown encoding results in MemoryError, which is not helpful

I will only backport the segfault fix.  I'll let Anthony decide if he wants
the other changes backported.  I will do the backport if asked.
diff --git a/Lib/test/bad_coding.py b/Lib/test/bad_coding.py
new file mode 100644
index 0000000..971b0a8
--- /dev/null
+++ b/Lib/test/bad_coding.py
@@ -0,0 +1 @@
+# -*- coding: uft-8 -*-