Merge "Remove Android-specific change to override open() mask." into rvc-dev am: acf86e92ba am: 9b8fc1c0ed am: 4e3b3b535f

Original change: https://googleplex-android-review.googlesource.com/c/platform/libcore/+/10511505

Change-Id: Id882ee9279e92a12ee847d0616419fa3ef36905c