Fix breakpoint doesn't work in multiprocessing

[MeditationDuck]

Description

The default breakpoint will just open the default debugger. and it does not work for multiprocessing, since tests are working as a child process.

This solves the problem.

• Using a custom breakpoint hook establishes communication with the parent process.
• Using a custom debugger that manages the communication's ending.

When the user types > quit in the debugger, quit the debugger and those child process statuses will be finished.

When the user type > continue in the debugger, the tests continue, and communication ends, and it will wait until the next breakpoint of all running tests.

When the user selects not to open the debugger, it does not open the debugger and execute. The behavior is the same as > continue.

Still, some deadlock remaining and currently using pdb, not ipdb. Those are required to be fixed.

Related Tickets & Documents

• Related Issue #

• Closes #

• I clicked on "Allow edits from maintainers"

[MeditationDuck]

Now it uses ipdb and it does termination of communication between the child process and the parent process same as exceptional handler.

[michprev]

Merged in #349