tests: context: allow 2 ticks of slop
tests: context: allow 2 ticks of slop

The hard-coded value of 10ms doesn't take the system configured
amount of ticks per second, nor does it account for an unlucky
tick advance which causes the test to fail very intermittently
in QEMU.

Signed-off-by: Andrew Boie <aab045b28152628be6af0e556050d0381fd0a34d@intel.com>

bigdinotech/zephyr,bigdinotech/zephyr,bigdinotech/zephyr,bigdinotech/zephyr,bigdinotech/zephyr