Trim redundant transitions instead of just skipping over them when looking for extension transition types.  This avoids a problem when the first future-specification transition occurs before the (y2038_boundary - 1) transition added to workaround Qt bug 53071.
Trim redundant transitions instead of just skipping over them
when looking for extension transition types.  This avoids a problem
when the first future-specification transition occurs before the
(y2038_boundary - 1) transition added to workaround Qt bug 53071.

Jellybooks/cctz,google/cctz,Jellybooks/cctz,google/cctz,Jellybooks/cctz