[libcxx] Reenable ranges for clang-cl

This reverts a224bf8e and fixes the
underlying issue.

The underlying issue is simply that MSVC headers contains a define
like "#define __in", where __in is one macro in the MSVC Source
Code Annotation Language, defined in sal.h

Just use a different variable name than "__in"
__indirectly_readable_impl, and add "__in" to nasty_macros.h just
like the existing __out. (Also adding a couple more potentially
conflicting ones.)

Differential Revision: https://reviews.llvm.org/D101613