I have been using go for about a year now, and the language has continually improved since then. Things are changing, improving, (somewhat) stabilizing, and generally amazing me in their innovations (e.g. gofix). It is most certainly not dying, and they seem to be putting quite a bit of effort into it.
The Google code page shows 17 people contributing to the project. From the looks of it, all but three of them are likely Google employees: http://code.google.com/p/go/people/list.
Worth noting is that the go project has notable programmers such as Rob Pike and Ken Thompson working for it, fathers of UNIX. If Google didn't care about the future of the go language, it is unlikely they would assign such high-profile programmers to its development.
Google is using go internally: http://golang.org/doc/go_faq.html#Is_Google_using_go_internally
The oracle saga won't happen with go: See the licence file and the irrevocable patent grant. Even if Google were to stop developing go (which is unlikely, given my points above), someone else would likely pick it up.
In addition to all of the above points, Google go is pretty much ideal for Google's internal use, due to it's built-in parallelization, native library support for the http protocol, and speed. For this reason alone, you can be pretty confident that go will be supported by Google for a while to come.
Best Answer
This is probably the closest you will get to an answer. Without talking to someone who actually worked on the project. Or more information is released to the public.
The link above contains this answer. It would have been hard to get point across without images. I would appreciate if you give the original poster up votes as well if you found this answer useful.
UPDATE: Google have just published a blog article called Google Instant, behind the scenes. It's an interesting read, and obviously related to this question. You can read how they tackled the extra load (5-7X according to the article) on the server-side, for example. The answer below examines what happens on the client-side:
Examining with Firebug, Google is doing an Ajax GET request on every keypress:
I guess it's working the same way as the auto completion. However this time, it also returns the search results of the partially complete search phrase in JSON format.
Examining one of the JSON responses while typing "Stack Overflow":
We can see that the JSON response contains the content to construct the search results as we type.
The formatted JSON responses look something like this: