Consolidates all methodDependencies files into one per split point.

Review at http://gwt-code-reviews.appspot.com/1453802

Review by: dconnelly@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10247 8db76d5a-ed1c-0410-87a9-c151d255dfc7