tests/samples: use platform_key on cmsis_rtos tests/samples

Coverage for cmsis rtos APIS should is provided using simulation, we
should not build those on every platform we have. Avoid failures due to
incompatiblities in requirements coming from various boards and also
reduce churn and noise during testing and CI.

Fixes #80215

Signed-off-by: Anas Nashif <anas.nashif@intel.com>