Prevent the infinite opening of debuggers

[StevenCostiou]

In certain cases, it happens that the system tries to open debuggers in loop, for instance:

• A loop with a failure in your code, in case it runs in a separate process from the UI's
• A debugger that opens successfully but whose contents triggers the opening of another debugger, and so on

In both cases, it causes the image to hang. The idea is to first prevent that hanging by giving back the hand to the user with information about the problem. A second step would be to give users a means to debug that problem (i.e., a safe debugger opening).

[StevenCostiou]

This concerns issues #8146 #8379 #8324 and maybe #2410 #7394 #5878. These issues are all (I think) about another problem, however the investigation of those problems are blocked by infinite debugger openings.