Fix doctest failure introduced by r57949.
The formatting of errors from pdb's own print command is different
from the formatting of errors when pdb exec's an arbitrary command;
the introduction of print as a pdb command caused this test to use
the former instead of the latter, causing the test to fail.
diff --git a/Lib/test/test_doctest.py b/Lib/test/test_doctest.py
index ab0e1d0..250614e 100644
--- a/Lib/test/test_doctest.py
+++ b/Lib/test/test_doctest.py
@@ -1792,7 +1792,7 @@
> <doctest foo[1]>(1)<module>()
-> calls_set_trace()
(Pdb) print(foo)
- *** NameError: name 'foo' is not defined
+ *** NameError: NameError("name 'foo' is not defined",)
(Pdb) continue
(0, 2)
"""