Proactively gathers more method names for MethodArgNamesLookup.  Before this
logic was only interested in abstract methods.  Now it collects any non local methods
with at least one argument.

Review at http://gwt-code-reviews.appspot.com/1359801


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@9730 8db76d5a-ed1c-0410-87a9-c151d255dfc7