tests: drivers: Verify NRF GPIO driver with GPIO_NRFX_INTERRUPT=n

Verify NRF GPIO driver with NRFX interrupts disabled.
Verify that driver handles properly 'get' and 'set' api methods.
When calling interrupt enable driver should report
'function not implemented' error.

Signed-off-by: Bartosz Miller <bartosz.miller@nordicsemi.no>