Allow the ART module to use "libc++fs". am: 978cfa2e7a am: 58e61553fa am: 8dbeb2515c am: c46a9ee0dc

Original change: https://android-review.googlesource.com/c/platform/external/libcxx/+/1890116

Change-Id: I71078c263de840cc2e44c2e46557567a720e5b8f