Well, we don't really know, because we've never bothered to build a chip/fab process with that capability. It's cheaper to just throw broken ones away (edit: plus, it isn't morally reprehensible to throw them away because they don't have consciousness... yet). I guess the other thing is that a CPU is pretty simplistic compared to a big organism.

We do bin products and then e.g. underclock or disable parts of them accordingly. So there's the start of an "injury"-sensing mechanism. But microchips still have a few thousand years to go in their "evolution" at least :)