Issue #20362: Honour TestCase.longMessage correctly in assertRegex.

Patch from Ilia Kurenkov.
diff --git a/Misc/ACKS b/Misc/ACKS
index 59828fb..7418d02 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -786,6 +786,7 @@
 Dave Kuhlman
 Jon Kuhn
 Toshio Kuratomi
+Ilia Kurenkov
 Vladimir Kushnir
 Erno Kuusela
 Ross Lagerwall