This test is used to check if the kernel scheduler

1. supports priority inheritance.
2. utilize the sync flag.

It also make statistic on average, best and worst latency
as well as number of deadline miss with a configurable
deadline specified in us.

The output is in json format hopefully to make it easy
to integrated with present test framework.

usage:

./schd-dbg                   # test and output json
./schd-dbg -i 1              # number of iterations
./schd-dbg -pair 4           # number of process pairs
./schd-dbg -deadline_us 2500 # deadline in us
./schd-dbg -v                # debug

Test: pixel
Change-Id: Idccf0d402dcd7b81c639020364b5ee32075e18cb