Thanks to Jeremy Barnes for pointing it out.
This reverts commit 909a5b3. Will fix inside V8's String::New instead.
Plus make inclusion order a little more consistent in general
+ Utf8Length is really slow but has the same semantics in this case
In order to do this, buffer data management was moved out of the JS entry-point New, and into Replace. Secondly, the constructor makes an immediate call to Replace, and in order for ArrayData calls to work, wrapping must already be set up. Now, the constructor takes the wrappee as a parameter.