[Crosswalk-Mini][Android] LZMA compression support

Use lzma compress libxwalkcore.so to reduce apk size.
refer to https://developer.android.com/reference/java/io/File.html, I do not think exists() or mkdirs() will throw exception. Instead you need check the return value.

And since there is only one place to use this function and short body, I'd suggest move logic into where it used.