ztest: cleanup phase should reset the timeout queue.
ztest: cleanup phase should reset the timeout queue.

Reusing the k_thread structure requires a cleanup of all essential
info. We need to remove the ztest_thread information from the timeout_q.

If left untouched, when a tick occurs the thread's delta_ticks_from_prev
would be corrupted. This inturn causes a chain reaction of problems.
Thus once the unit test is completed the timeout_q is scrubbed.

Signed-off-by: Adithya Baglody <06b44f6fa9a97a2b955c2d2cd070279967447860@intel.com>

kraj/zephyr,ldts/zephyr,zephyriot/zephyr,explora26/zephyr,nashif/zephyr,zephyriot/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,explora26/zephyr,finikorg/zephyr,mbolivar/zephyr,mbolivar/zephyr,kraj/zephyr,explora26/zephyr,ldts/zephyr,nashif/zephyr,galak/zephyr,zephyriot/zephyr,zephyriot/zephyr,galak/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,GiulianoFranchetto/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,Vudentz/zephyr,punitvara/zephyr,explora26/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,ldts/zephyr,kraj/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,zephyriot/zephyr,mbolivar/zephyr,kraj/zephyr,Vudentz/zephyr,punitvara/zephyr,nashif/zephyr,kraj/zephyr,ldts/zephyr,nashif/zephyr,punitvara/zephyr,nashif/zephyr,explora26/zephyr,mbolivar/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,punitvara/zephyr,Vudentz/zephyr,finikorg/zephyr,GiulianoFranchetto/zephyr,galak/zephyr,Vudentz/zephyr,ldts/zephyr,finikorg/zephyr,Vudentz/zephyr,Vudentz/zephyr,mbolivar/zephyr,punitvara/zephyr