tests: kernel: added clock_test

tests/kernel/common:
added test case to cover kernel clocks service.
https://www.zephyrproject.org/doc/kernel/timing/clocks.html



Jira: ZEP-1242

Change-Id: I40a06dd9d4dcb1ed24d488088eb2e456740c3bad
Signed-off-by: Sharron LIU <sharron.liu@intel.com>