tests: kernel: Fix assumption in test_kernel_cpu_idle
tests: kernel: Fix assumption in test_kernel_cpu_idle

test_kernel_cpu_idle assumes that CPU's next timer wakeup will be
1 millisecond in the future based on kernel timer it sets. Move tick
synchronization delay into test loop so this will always be the case.

Fixes #41347

Signed-off-by: Daniel DeGrasse <002dd1d4ac44ebb71088aae93501e62b784ed821@nxp.com>

galak/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,finikorg/zephyr,galak/zephyr