Merge "libc++fs is part of libc++ now." into main am: 86719bfe48

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/3129259

Change-Id: I7d55d955cbda13fb86e829ba21f92e6415d8c3a5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>