Two (more) flask tests fail with flask 2.2.2

[juliangilbey]

When testing pydevd (as at git commit 8ee4065) with flask 2.2.2, the following two tests failed:

tests_python/test_debugger.py::test_case_flask
tests_python/test_debugger_json.py::test_case_flask_line_validation

The cause was the same in both cases - there was unexpected stderr output:

----------------------------- Captured stderr call -----------------------------
stderr: WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
stderr:  * Running on http://127.0.0.1:43701
stderr: Press CTRL+C to quit
stderr: 127.0.0.1 - - [24/Sep/2022 07:11:00] "GET / HTTP/1.1" 200 -

I don't know if there's a way to silence this warning during tests.