tst_qbluetoothlocaldevice::tst_pairDevice doesn't pass in manual mode on Windows

tst_qbluetoothlocaldevice::tst_pairDevice doesn't pass in manual mode on Windows.

Manual mode here means that the BT_TEST_DEVICE environment variable is set, which means manual pairing interaction with another device.

At this point it is not certain why there are fails, but there are some suspicions:

• requestPairing's pairingFinished() signal and pairingStatus() seem to give different pairing statuses
• sometimes pairing operation results in "AlreadyPaired" status from Windows, but since the code only expects "Paired" for successful case, it is interpreted as an error