Revert r136547, r136545, and r136542 by removing slist.

This was checked in without review. It is not clear its reasonable to
include with libc++ at all, and needs discussion at a highlevel before
moving forward.

It's also completely lacking tests, and included several bugs in the
implementation.

git-svn-id: https://llvm.org/svn/llvm-project/libcxx/trunk@136577 91177308-0d34-0410-b5e6-96231b3b80d8
1 file changed