[llvm] Extend the mismatch attr check to all MayBeDerefined function (PR #88035)

[Lei Wang via llvm-commits]

wlei-llvm wrote:

> Looks good in general; 1 nit before merging: should be "redfined", not "derefined".

I see. Here both refinement and de-refinement can lead to a different version of IR (the checksum mismatch) in link time. How about just use "NonExactDefinition"? 
(I thought the opposite of the `isDefinitionExact` was `Derefined` while I was looking at the code..)
```
  bool isDefinitionExact() const {
    return !mayBeDerefined();
  }
``` 

https://github.com/llvm/llvm-project/pull/88035