Camera: Use non-null video recording paths

Legacy video recording test cases will try to use
"/dev/null" as default output file path which is
no longer supported.
Use a valid storage location like similar Camera2
recording test cases.

Bug: 157291505
Test: Camera CTS
atest
cts/tests/camera/src/android/hardware/cts/CameraTest.java#testLockUnlock
atest
cts/tests/camera/src/android/hardware/cts/CameraTest.java#testRecordingHint
atest
cts/tests/camera/src/android/hardware/cts/CameraTest.java#testVideoSnapshot

Change-Id: Iae625a0696e435036097d4f77e11738aade1806b
1 file changed