Time drifting test cases use serial communication with the host and are unstable on CI.
Skip time-drifting test cases if SKIP_TIME_DRIFT_TESTS macro is defined.
The idea for the future is to use FPGA test shield for timing tests instead of host scripts.
Also remove `__ARM_FM` macro which in most cases was used to disable time drifting tests. In other cases replace `__ARM_FM` with `TARGET_ARM_FM` which is more suitable.