Remove partially proven and unused lemma common_of_halves_subrange
Remove partially proven and unused lemma common_of_halves_subrange

Lemma was:

     Lemma common_of_halves_subrange:
      forall r1 r2 r,
      rNonneg r ->
      (0 < rBits r)%N ->
      isSubrange r1 (halfRange r false) ->
      isSubrange r2 (halfRange r true) ->
      r = commonRangeDisj r1 r2.

Maybe I will remember this if I need it after all.

antalsz/hs-to-coq,antalsz/hs-to-coq