ExpressionAnalyzer fix for clinit field refs.

Fixes a bug in ExpressionAnalyzer were clinit-triggering field refs were not being considered.  This could cause bugs in the inliner where clinits would be dropped.

Found by: spoon
Review by: spoon

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@7310 8db76d5a-ed1c-0410-87a9-c151d255dfc7