No. What those do is make you breathe through tiny holes and limit your breathing and that's not very convenient for CF'ers and the opposite of what we want. Especially when excercising.
(The PEP mask on the exhale that we use to bring up gunk is a different story.)
Athletes do high altitude training mainly to increase their red blood cell count (which carry oxygen around) and it does not directly increase their lungfunction.
Even if such a mask could provoke an increase in red blood cells the effect for us would be far too small to notice. Worse, if we needed that then the negatives of using such a mask would be too great. (Ie: We'd be unconscious)
Ofcourse we get "high altitude training" anyway for free (without needing any Batman villain type masks) as our lungfunction decreases..
(That's not to say you shouldn't go out and buy any Batman villain type masks just not these)