Direct archive XWalkCoreShell.apk for mini project

As it's the main target for us to measure our binary size.
[Android][Mini] Remove ICU dependency for crosswalk

By using gyp flag use_icu_alternatives_on_android.
The changes in DEPS.xwalk will introduce the ICU dependency
removing efforts.

TODO(wang16):
1. The icu code is still contained in libxwalkcore.
   Only icudtl.data is removed in apk right now.
   Next is to remove all the dependencies to icu target from gyps.
2. The icudtl.data is still contained in the built packages
   including xwalk_core_library.tar.gz and xwalk_app_template.tar.gz.
Merge pull request #2569 from wang16/mini_remove_icu

[Android][Crosswalk Mini] Remove ICU dependency for crosswalk