Cancel pending tasks by callling underTest.onPause to avoid mockito-npe

KeyguardPasswordViewController extends KeyguardAbsKeyInputViewController
which can have mPendingLockCheck. Call #onPause to cancel the pending
lock check so we don't have it running after we finish running
the test and the mocks are null (causing npe).

Also add mock for keyguardMessageArea.resources in case
the pending lock check occurs before the test ends.

Re-enables KeyguardPasswordViewControllerTest.

Flag: EXEMPT test only fix
Fixes: 423646800
Test: atest KeyguardPasswordViewControllerTest
Change-Id: Icc9765a55a2375ee59359fa940879ebc07be9cf4