Automatically stop on failed test

[KES777]

It would be handy to automatically call $DB::single = 1 when test fail

STOP_WHEN_FAIL=1 perl -d t/some_test.t

This brings me at problem place precisely. And allow dig problem without interruption

[exodist]

I think this would best be done as a plugin in Test2::Suite similar to DieOnFail or BailOnFail.

[exodist]

@KES777 Test-More/Test2-Suite#267 Tell me if this does what you would like. I do not usually use the debugger, so not able to verify on my end.