Fix cell usage calculation for menu items with text

This prevents an edge case where menu items with text have 1 available cell and end up using it, thus overlapping the overflow button.

This is based on Android 4.2.2's code for ActionMenuView: http://grepcode.com/file/repository.grepcode.com/java/ext/com.google.android/android/4.2.2_r1/com/android/internal/view/menu/ActionMenuView.java#ActionMenuView.measureChildForCells%28android.view.View%2Cint%2Cint%2Cint%2Cint%29