tests: gpio: add tests for GPIO_DT_RESERVED_RANGES_NGPIOS et al

Added basic test coverage for the:

   * GPIO_DT_RESERVED_RANGES_NGPIOS,
   * GPIO_DT_RESERVED_RANGES,
   * GPIO_DT_INST_RESERVED_RANGES_NGPIOS,
   * GPIO_DT_INST_RESERVED_RANGES,
   * GPIO_DT_PORT_PIN_MASK_NGPIOS_EXC,
   * GPIO_PORT_PIN_MASK_FROM_DT_NODE,
   * GPIO_DT_INST_PORT_PIN_MASK_NGPIOS_EXC and
   * GPIO_PORT_PIN_MASK_FROM_DT_INST macros.

Signed-off-by: Andrey VOLKOV <andrey.volkov@munic.io>