android/ion: userspace test utility for ion buffer sharing

This is a test utility to verify ION buffer sharing in user space
between 2 independent processes.
It uses unix domain socket (with SCM_RIGHTS) as IPC to transfer an FD to
another process to share the same buffer.
This utility demonstrates how ION buffer sharing can be implemented between
two user space processes, using various heap types.

This utility is made to be run as part of kselftest framework in kernel.
The utility is verified on Ubuntu-32 bit system with Linux Kernel 4.14,
using ION system heap.

For more information about the utility please check the README file.

Signed-off-by: Pintu Agarwal <pintu.ping@gmail.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>