tests: cmsis_rtos_v2: Bugfix in test which leads to random errors
tests: cmsis_rtos_v2: Bugfix in test which leads to random errors

Fix a quite silly bug in the testcase which led to random failures
on execution.

Signed-off-by: Alberto Escolar Piedras <52be3174920ed06cbdfbcf9622a1a6c68e942617@oticon.com>

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