Revert "TaggedUnion: add a lemma wrapping Pointer.no_upd_lemma_1"
Revert "TaggedUnion: add a lemma wrapping Pointer.no_upd_lemma_1"

This reverts commit 63ee502bd732293c4403a4821d2b7f1cb669b98f.

FStarLang/FStar,A-Manning/FStar,FStarLang/FStar,A-Manning/FStar,FStarLang/FStar,A-Manning/FStar