Merge "Revert "Remove std::char_traits for non-standard types"" into main am: 506a3060cf

Original change: https://android-review.googlesource.com/c/platform/external/libcxx/+/3001098

Change-Id: I80b74fab6b47b3a8562137af341629475cfb1b17
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>