Add a sample service for testing init.

I find myself using something like this every time I add functionality
to init. I cannot possibly be the only one doing this. On the other
hand, if this hasn't been added for so long, maybe there's a reason
for that.

The advantage of using a test service versus modifying an existing
service is that the test service doesn't *require* any permissions or
privileges, so you can add and/or remove whatever you need to test
without breaking the service.

I found it useful to have the service check its own /proc/<pid>/status
from command-line arguments, so that's what the service does.

This CL also adds a .clang-format file for init.

Bug: None
Test: Service runs and exits successfully.

Change-Id: I3e7841a7283158e10c0bf55e0103c03902afb1f0
6 files changed