sanitycheck: delete the '\r' char in front of serial output
sanitycheck: delete the '\r' char in front of serial output

add lstrip function to delete the '\r' char in front of the
serial output from serail readline, because this '\r'
will influence the result match function in harness.py.

Signed-off-by: peng1 chen <a9104ed43ee1e05962395401b47b879b137cfacf@intel.com>

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