#7110: have regrtest print test failures and tracebacks to stderr not stdout.

Patch by Sandro Tosi.
diff --git a/Misc/ACKS b/Misc/ACKS
index 5d12c1f..228dfe7 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -818,6 +818,7 @@
 R Lindsay Todd
 Bennett Todd
 Matias Torchinsky
+Sandro Tosi
 Richard Townsend
 Laurence Tratt
 John Tromp