Fix Coverity Defect Report 115524 in G4DebuggingTools

Coverity doesn't pick up that creating a fatal `G4Exception` instance
causes that exception to be thrown and execution of the current function
to stop. The work-around is to add calls to `abort()` just after the
`G4Exception` is created.


Former-commit-id: d2d10c374c412c0f61ac927f67085b1ae30d794c