Merge "libc++fs is part of libc++ now." into main am: 5b7e5350a6

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/3128499

Change-Id: I4afba61c7fea905b90087c9716d6a39879e536dc
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>