Merge "libc++fs is part of libc++ now." into main am: 74aef3202a

Original change: https://android-review.googlesource.com/c/platform/system/extras/+/3113942

Change-Id: Ida3e915e65e41ab9da0122755eba151983fe43c1
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>