[libc++] Mark __cpp_lib_hardware_interference_size as unimplemented. This fxes bug PR41423.

Summary:
As described in the bug report:
The commit a8b9f59e8caf378d56e8bfcecdb22184cdabf42d "Implement feature test macros using a script" added test features macros for libc++. Among others, it added `__cpp_lib_hardware_interference_size`. However, there is nothing like std::hardware_constructive_interference_size nor std::hardware_destructive_interference_size, that should be in header <new>.

* https://bugs.llvm.org/show_bug.cgi?id=41423

Reviewed By: ldionne, #libc

Differential Revision: https://reviews.llvm.org/D80431