Merge "libc++fs is part of libc++ now." into main am: 546e89303a

Original change: https://android-review.googlesource.com/c/platform/system/extras/+/3113999

Change-Id: Iefd523fa6d46412072e5ea8165b31bf896698cbb
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>