Flaky internet tests: use python3-pytest-rerunfailures NOT python3-flaky
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Internet tests (command2) may be flaky depending on the available
internet connection.

Upstream manages this via
  flaky_pdb_dl = pytest.mark.flaky(rerun=3, reason="github-node flaky pdb dl")
defined in tests/conftest.py.

Despite the name of the pytest mark, this pytest.mark.flaky is
provided by python3-pytest-rerunfailures and NOT by python3-flaky.
That is, rerunfailures supports the rerun option, and flaky does not.

pytest gives priority to the flaky plugin over the rerunfailures plugin.
The tests that use the flaky_pdb_dl mark will therefore FAIL if
python3-flaky is installed, even if python3-pytest-rerunfailures is
also installed.

autopkgtest allows test package Depends to be declared in
debian/tests/control, but not Conflicts.

Therefore in order to successfully run debian CI tests (autopkgtests),
in particular to test command2, you must (manually) ensure that
python3-flaky is NOT installed.
