Clean up compatible utility classes

java/src/com/android/inputmethod/compat/CompatUtils.java

...ndroid/inputmethod/compat/DownloadManagerCompatUtils.java

...d/inputmethod/compat/InputMethodManagerCompatWrapper.java

...oid/inputmethod/compat/InputMethodSubtypeCompatUtils.java

...c/com/android/inputmethod/compat/SuggestionSpanUtils.java

...android/inputmethod/compat/UserDictionaryCompatUtils.java

java/src/com/android/inputmethod/compat/ViewCompatUtils.java

.../inputmethod/keyboard/internal/MoreKeySpecSplitTests.java