uasyncio.core: Add test for callback args to call_soon().

uasyncio.core/test_cb_args.py

@@ -0,0 +1,16 @@
+try:
+    import uasyncio.core as asyncio
+except:
+    import asyncio
+
+
+def cb(a, b):
+    assert a == "test"
+    assert b == "test2"
+    loop.stop()
+
+
+loop = asyncio.get_event_loop()
+loop.call_soon(cb, "test", "test2")
+loop.run_forever()
+print("OK")