Merge "Document that ASharedMemory_create fds may or may not be CLOEXEC." am: 9e499bc47f am: 6b7a48e022 am: 3767a044ff

Original change: https://android-review.googlesource.com/c/platform/frameworks/native/+/1419344

Change-Id: I715f24c79e0cf1833f35f04a8b76fedb21504cbe