Chrome uses OS X's CoreText for rendering the tab titles, but uses its own text rendering engine for the site body. CoreText is the one that crashes on that unicode.
Meanwhile on Chromium 26.0.1384.0 (build 176849) on OS X Lion everything is fine for me. The titlebar is (appropriately for the typography) messed up, but there are no tab loading issues, cpu/memory spikes, or screen corruption. The closest thing to an issue I see is that it makes using Witch's window switch dialogue a bit ugly. Contrary to the thread on jwz's journal YoruFukurou 2.77 doesn't crash or misbehave for me viewing that tweet, but behind the scenes fontd uses up a decent chunk of cpu for several seconds. Perhaps Mountain Lion has more severe bugs in CoreText?
And apparently Twitter puts the content of a tweet in the <title> tag if you are on the page for a single tweet. Surprised that doesn't cause more problems.
> And apparently Twitter puts the content of a tweet in the <title> tag if you are on the page for a single tweet.
Nope, Twitter uses a shortened, ellipsized version of the tweet as <title> ... </title>. Still, if there's Unicode in the shortened version, it might have the same outcome.
After reducing the html-code in the site, it seems to me that it is not the title that causes the crash, but the p-tag with the specific css-style applied.