The commits are all there, the fixes just might not look completely obvious. We (chromium) commit all fixes to the chromium repository before pushing them to users, always.
In IE9 h/w acceleration and Direct Write are controlled by the document's rendering mode. Hacker News renders in quirks modes and thus uses GDI. Try forcing the document to render in IE9 mode (open the F12 developer tools, hit Alt-9) and the text will look much closer to Firefox 4's. The page layout will also break a bit.