Use CircuitPython _TICKS_PERIOD
Use CircuitPython _TICKS_PERIOD

.. since Adafruit_CircuitPython_asyncio is hard-coded to this _TICKS_PERIOD
not the one that would otherwise be used on Unix

This fixes all the uasyncio test failures on Unix

adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython,adafruit/circuitpython