[libc++][ranges] Updated `[[nodiscard]]` implementation for `subrange` and `join_with_view` (#176936)

Added or removed `[[nodiscard]]` according to the guidelines and updated
the tests.

 - https://libcxx.llvm.org/CodingGuidelines.html
 - https://wg21.link/range.subrange
 -  https://wg21.link/range.join.with.view

Towards #172124

NOKEYCHECK=True
GitOrigin-RevId: b232970172dd0df0c8ab6c8147b6bf81a477fa03