Split_goal: preserve trivial subgoals under "keep_on_simp"
Split_goal: preserve trivial subgoals under "keep_on_simp"

douglas-larocca/why3,jpdeplaix/why3,jpdeplaix/why3,ssaavedra/why3,douglas-larocca/why3,ssaavedra/why3,ssaavedra/why3,jpdeplaix/why3,douglas-larocca/why3