[3.11] gh-102541: Add test case for help() for non_existent_module (GH-106340) (#106640)

gh-102541: Add test case for help() for non_existent_module (GH-106340)

Test fix for when one enters, for instance, 'abd' at the 'help>' prompt.
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(cherry picked from commit 292ac4bfe92768140c2d383fd329cfa1949869b2)

Co-authored-by: Kirill Podoprigora <kirill.bast9@mail.ru>
Co-authored-by: Terry Jan Reedy <tjreedy@udel.edu>