Add action key test for Lxx theme

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

...method/keyboard/KeyboardLayoutSetActionLabelKlpTests.java

...method/keyboard/KeyboardLayoutSetActionLabelLxxTests.java

...tmethod/keyboard/KeyboardLayoutSetSubtypesCountTests.java

...roid/inputmethod/keyboard/KeyboardLayoutSetTestsBase.java

...id/inputmethod/keyboard/layout/tests/LayoutTestsBase.java