intel_s1000: tests: introduce tests to check features enabled

This patchset carries out basic tests on the features supported
on intel_s1000. Currently, Interrupt mechanism, GPIO handling, I2C
communication and UART prints are illustrated.

Change-Id: I7ea03b5085b7fa8d29635c294038536465a70660
Signed-off-by: Rajavardhan Gundi <rajavardhan.gundi@intel.com>
Signed-off-by: Anas Nashif <anas.nashif@intel.com>