more detailed test and fix IE8 expectation

git-svn-id: svn://svn.code.sf.net/p/htmlunit/code/trunk@8528 5f5364db-9458-4db8-a492-e30667be6df6
use the correct accept header (work in progress)
Issue 1245


git-svn-id: svn://svn.code.sf.net/p/htmlunit/code/trunk@8529 5f5364db-9458-4db8-a492-e30667be6df6