Merge "libc++fs is part of libc++ now." into main am: 8392c70770

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/3126193

Change-Id: Id89ee23b0dd3e425c3b83e6fce7d93a4ed1096a6
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>