removing a redundant ghost check in must_erase_for_extraction, already accounted for by Env.is_erasable_effect, review comment from Aymeric
removing a redundant ghost check in must_erase_for_extraction, already accounted for by Env.is_erasable_effect, review comment from Aymeric

FStarLang/FStar,FStarLang/FStar,FStarLang/FStar