Merge "libc++fs is part of libc++ now." into main am: 7b155a8ac1

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/3122731

Change-Id: I16ec6a58d2a0ec08b48ea87a04fc5cebd41ff35d
Signed-off-by: Automerger Merge Worker <[email protected]>