[3.14] gh-108885: Imporove tests for doctest (GH-134832) (GH-134855)

Test the error and failure report in more detail.
(cherry picked from commit f6324bc7ee)

Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>

Lib/test/test_doctest/sample_doctest_errors.py

@@ -0,0 +1,46 @@
+"""This is a sample module used for testing doctest.
+
+This module includes various scenarios involving errors.
+
+>>> 2 + 2
+5
+>>> 1/0
+1
+"""
+
+def g():
+    [][0] # line 12
+
+def errors():
+    """
+    >>> 2 + 2
+    5
+    >>> 1/0
+    1
+    >>> def f():
+    ...     2 + '2'
+    ...
+    >>> f()
+    1
+    >>> g()
+    1
+    """
+
+def syntax_error():
+    """
+    >>> 2+*3
+    5
+    """
+
+__test__ = {
+    'bad':  """
+        >>> 2 + 2
+        5
+        >>> 1/0
+        1
+        """,
+}
+
+def test_suite():
+    import doctest
+    return doctest.DocTestSuite()