Remove unnecessary methods of KeyboardSwitcher

...rc/com/android/inputmethod/keyboard/KeyboardSwitcher.java

...rc/com/android/inputmethod/keyboard/MainKeyboardView.java

.../android/inputmethod/keyboard/internal/KeyboardState.java

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

...id/inputmethod/latin/suggestions/SuggestionStripView.java

...d/inputmethod/keyboard/internal/MockKeyboardSwitcher.java