Fix tab key's navigation behavior

java/res/xml-sw600dp/key_styles_common.xml

java/res/xml-sw768dp/key_styles_common.xml

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

java/src/com/android/inputmethod/latin/InputAttributes.java

java/src/com/android/inputmethod/latin/LatinIME.java

java/src/com/android/inputmethod/latin/SettingsValues.java