check rspy.test.check_frame_drops() to be a bit more informative
check rspy.test.check_frame_drops() to be a bit more informative

(cherry picked from commit bc0aab071dddf64a42c8c04ad4367f6d8cdaa2ba)

IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense,IntelRealSense/librealsense