Revert "tests: devicetree: test supported devices API"
Revert "tests: devicetree: test supported devices API"

This reverts commit 4c32e21fc765a63a351d410991a11d14fbdfdf30 with some
manual conflict resolution.

It's not clear that the supported devices are being properly computed,
so let's revert this for v2.7.0 until we've had more time to think
it through.

Signed-off-by: Martí Bolívar <9d90ac4c7bf6a305f6bfd81a23c7859bc883380e@nordicsemi.no>

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