CUTE Test launch configuration should warn for missing executable

[tpecar]

Starting a launch configuration with build settings set to auto-build

may cause the launch to silently fail, because the build removes the previous executable.

While this is essentially project misconfiguration that can be fixed at Project > Properties >C/C++ Build >Refresh Policy,
it would be beneficial if the launch configuration would warn the user for missing files / would invoke project refresh in this case.