Fix possible NPE while finding device override value from resource

java/res/values-land/keyboard-heights.xml

java/res/values/keyboard-heights.xml

java/res/values/keypress-vibration-durations.xml

java/res/values/keypress-volumes.xml

java/res/values/phantom-sudden-move-event-device-list.xml

.../src/com/android/inputmethod/keyboard/PointerTracker.java

.../src/com/android/inputmethod/latin/settings/Settings.java

...rc/com/android/inputmethod/latin/utils/ResourceUtils.java

...m/android/inputmethod/latin/utils/ResourceUtilsTests.java