This test was written to assume that on idle the CPU would wake up on
the next tick boundary because of the timer interrupt. No such
interrupt arrives in tickless mode and it hangs forever.
A more whiteboxy test involving setting a clock timout will have to be
written for this feature if we want to keep it on tickless systems.
Alternatively we could move this test out of tests/kernel/context and
always disable tickless.
Signed-off-by: Andy Ross <andrew.j.ross@intel.com>