bpo-35742: Fix test_envar_unimportable in test_builtin. (GH-11561)


Handle the case of an empty module name in PYTHONBREAKPOINT.

Fixes a regression introduced in bpo-34756.
(cherry picked from commit 3607ef43c4a1a24d44f39ff54a77fc0af5bfa09a)

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