tests: remove redundant APPLICATION defines

tests/bitarithm_timings/Makefile

tests/bloom_bytes/Makefile

tests/board_calliope-mini/Makefile

tests/board_microbit/Makefile

tests/buttons/Makefile

tests/cbor/Makefile

tests/conn_can/Makefile

tests/cpp11_condition_variable/Makefile

tests/cpp11_mutex/Makefile

tests/cpp11_thread/Makefile

tests/driver_adcxx1c/Makefile

tests/driver_adt7310/Makefile

tests/driver_adxl345/Makefile

tests/driver_apa102/Makefile

tests/driver_at30tse75x/Makefile

tests/driver_at86rf2xx/Makefile

tests/driver_bh1750/Makefile

tests/driver_bmp180/Makefile

tests/driver_bmx280/Makefile

tests/driver_dht/Makefile