The `__main__` module imported in the `_pyrepl` module points to the `_pyrepl` module itself when the interpreter was launched without `-m` option and didn't execute a module,
while it's an unexpected behavior that `__main__` can be `_pyrepl` and relative imports such as `from . import *` works based on the `_pyrepl` module.
(cherry picked from commit b1b8962443)
Co-authored-by: Yuichiro Tachibana (Tsuchiya) <t.yic.yt@gmail.com>
Co-authored-by: Łukasz Langa <lukasz@langa.pl>
