Allow --no-loader-dupe-check along with --show=left

[solardiz]

It appears that john.conf setting NoLoaderDupeCheck = Y has effect on the --show=left option, speeding it up for huge hash lists, yet the corresponding command line option --no-loader-dupe-check isn't currently allowed in this combination. It probably should be.

[solardiz]

This is tricky. We currently require FLG_CRACKING_CHK:

        {"loader-dupe-check", FLG_ONCE, 0, FLG_CRACKING_CHK, OPT_TRISTATE, NULL, &options.loader_dupecheck},

We do not support an OR condition in that field, only AND. We could instead require FLG_ACTION, but that would enable this option for too many possible actions, including e.g. --status where no password hash files are read and the option thus makes no sense. OTOH, seeing where else we set FLG_ACTION, I see this option could possibly also make set along with --make-charset (to be researched).

Ideally, we'd either introduce a new flag like FLG_LOADER and set it for all actions that involve the loader, or we enhance the option parser to support OR conditions (but how to indicate them? with an extra OPT_ bit perhaps?)