Merge "Split MOUNT_FLAG_VISIBLE into MOUNT_FLAG_VISIBLE_FOR_{READ, WRITE}" am: bddb449182 am: 6e9d37542f

Original change: https://android-review.googlesource.com/c/platform/system/vold/+/1891635

Change-Id: I5e3410dfe59791b003b6387a64e228b5945a99a5