[3.10] bpo-45238: Fix unittest.IsolatedAsyncioTestCase.debug() (GH-28449) (GH-28521)

It runs now asynchronous methods and callbacks.

If it fails, doCleanups() can be called for cleaning up.
(cherry picked from commit ecb6922ff2d56476a6cfb0941ae55aca5e7fae3d)

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