Code review comment for lp://qastaging/~afrantzis/mir/fix-1358191-connect-segv-spike

> we load everything to probe it, and then want to unload the platforms that didn't probe.

Then perhaps we can keep SharedLibrary as it is and add a SharedLibrary::make_permanent() member that ensures that the library is not unloaded on object destruction (or we could have SharedLibrary and PermanentSharedLibrary, or ... many options here :))