Merge "Revert "Remove std::char_traits for non-standard types"" into main am: 506a3060cf am: 2c69e245c7

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

Change-Id: I53981fea78ece8f877f47d610792cfbe2df3f1cd
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>