backport: #20145: assert[Raises|Warns]Regex now raise TypeError on bad regex.

Previously a non-string, non-regex second argument and missing callable
argument could cause the test to appear to always pass.

Initial patch by Kamilla Holanda.
diff --git a/Misc/ACKS b/Misc/ACKS
index 68617ce..0eb8267 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -546,6 +546,7 @@
 Albert Hofkamp
 Tomas Hoger
 Jonathan Hogg
+Kamilla Holanda
 Steve Holden
 Akintayo Holder
 Thomas Holenstein
diff --git a/Misc/NEWS b/Misc/NEWS
index 2a7cd3b..b00a017 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -24,6 +24,9 @@
 Library
 -------
 
+- Issue #20145: `assertRaisesRegex` and `assertWarnsRegex` now raise a
+  TypeError if the second argument is not a string or compiled regex.
+
 - Issue #21058: Fix a leak of file descriptor in
   :func:`tempfile.NamedTemporaryFile`, close the file descriptor if
   :func:`io.open` fails