The gflow constant analyzer assumes that parameters
could initially hold anything, rather than assuming
they haven't been initialized.  This caused problems
for code like:

foo(String param) {
if (something) {
param = null;
}
// at this point, analyzer thinks param==null
}

Review at http://gwt-code-reviews.appspot.com/405801


git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@7979 8db76d5a-ed1c-0410-87a9-c151d255dfc7