remfin: do not clone transitions that are accepting in main
* spot/twaalgos/remfin.cc (default_strategy): Detect transitions from the main copy that are completely accepting and that do not need to be repeated in the clones. * tests/python/remfin.py: Add a test case. * tests/core/ltl2dstar4.test: Improve expected results. * NEWS: Mention the change.