[libc++] Addresses LWG3358

  LWG3358 ยง[span.cons] is mistaken that to_address can throw

Since last - first has to throw tests are added to make sure this always
happens.

Depends on D142808

Reviewed By: #libc, ldionne

Differential Revision: https://reviews.llvm.org/D142843

GitOrigin-RevId: 508b4510de123c4cccc9440546da1f71a23cbb83
3 files changed