LWG 2447 is marked as `Complete`, but there is no `static_assert` to
reject volatile types in `std::allocator`. See the discussion at
https://reviews.llvm.org/D108856.
Add `static_assert` in `std::allocator` to disallow volatile types. Since this
is an implementation choice, mark the binding test as `libc++` only.
Remove tests that use containers backed by `std::allocator` that test
the container when used with a volatile type.
Reviewed By: ldionne, #libc
Differential Revision: https://reviews.llvm.org/D109056
LWG3175 identifies that the `common_reference` requirement for
`swappable_with` is over-constraining and doesn't need to concern itself
with cv- or reference qualifiers.
Differential Revision: https://reviews.llvm.org/D99817
moves tests into directories matching their stable names so that the
tests can reflect the concept name
Differential Revision: https://reviews.llvm.org/D99104
Joe Loser