Remove deprecated parameter for createTreeWalker.
Remove deprecated parameter for createTreeWalker.

The entityReferenceExpansion parameter for document.createTreeWalker is
deprecated and optional because EntityReferences didn't make it into the
standard.

a-nguyen/chromium-vim,aplaice/chromium-vim,zchee/chromium-vim,lululau/chromium-vim,aplaice/chromium-vim,aplaice/chromium-vim,a-nguyen/chromium-vim,andviro/chromium-vim,rever0f/chromium-vim,andviro/chromium-vim,lululau/chromium-vim,BlinkD/chromium-vim,1995eaton/chromium-vim,BlinkD/chromium-vim,andviro/chromium-vim,zchee/chromium-vim,lululau/chromium-vim,BlinkD/chromium-vim,andviro/chromium-vim,a-nguyen/chromium-vim,rever0f/chromium-vim,h43z/chromium-vim,lululau/chromium-vim,h43z/chromium-vim,1995eaton/chromium-vim,zchee/chromium-vim,rever0f/chromium-vim,BlinkD/chromium-vim,h43z/chromium-vim,h43z/chromium-vim,aplaice/chromium-vim,rever0f/chromium-vim,zchee/chromium-vim,a-nguyen/chromium-vim,1995eaton/chromium-vim,1995eaton/chromium-vim