GPIO- Interrupt on a non-interrupt pin?
Not directly, but if you have a periodic interrupt going for other purposes you could add a poll of your button in there. If you don't, you could add a periodic interrupt at some nominal rate (20-100ms) and poll your button there (assuming this is a human-pushed button, you don't need any more resolution than that).
This doesn't save you the wasted time of reading a button that hasn't changed, but it does save you the hassle of polling in the background.