#27364: fix "incorrect" uses of escape character in the stdlib.

And most of the tools.

Patch by Emanual Barry, reviewed by me, Serhiy Storchaka, and
Martin Panter.
diff --git a/Lib/test/test_email/test__header_value_parser.py b/Lib/test/test_email/test__header_value_parser.py
index f7ac0e3..26ece69 100644
--- a/Lib/test/test_email/test__header_value_parser.py
+++ b/Lib/test/test_email/test__header_value_parser.py
@@ -581,7 +581,7 @@
 
     def test_get_comment_quoted_parens(self):
         self._test_get_x(parser.get_comment,
-            '(foo\) \(\)bar)', '(foo\) \(\)bar)', ' ', [], '', ['foo) ()bar'])
+            r'(foo\) \(\)bar)', r'(foo\) \(\)bar)', ' ', [], '', ['foo) ()bar'])
 
     def test_get_comment_non_printable(self):
         self._test_get_x(parser.get_comment,
@@ -625,7 +625,7 @@
 
     def test_get_comment_qs_in_nested_comment(self):
         comment = self._test_get_x(parser.get_comment,
-            '(foo (b\)))', '(foo (b\)))', ' ', [], '', ['foo (b\))'])
+            r'(foo (b\)))', r'(foo (b\)))', ' ', [], '', [r'foo (b\))'])
         self.assertEqual(comment[2].content, 'b)')
 
     # get_cfws