So as you say good testers are really good at breaking things, so what makes a developer really good? Maybe there is a related skill seeing testing and developing are related (testers test/break what a developer builds). So then maybe a developer needs to be good at fixing what the tester breaks. Which would mean he lets go of his ego or pride in his own code and is able to accept that he/she writes flawed code and be really good at fixing or re-building it. I think it's been ruled out that developers are never going to always write the code correctly the first time (surely that can be a good goal to have, but not something to believe is going to actually happen) so maybe what sets apart a really good developer from a regular one is that he knows that his code is going to have flaws and is happy to hear about them so he can go fix them and improve and re-build his broken work.

Edit: another thought: maybe the developer should see his code as a problem rather than an answer so that he can constantly question it. Rather than being satisfied that something you wrote is now done or solved, instead you see it as something that has likely created new problems for you to be able to solve (Mark Manson said something insightful about this, how solutions don't really solve everything completely as it might solve 1 problem it always presents new problems/challenges)