Merge "libc++fs is part of libc++ now." into main am: 23655271e4

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/3128194

Change-Id: Idba4ae077655eb9c2469a6a44b01f55e1c2a293e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>