[llvm] [NFC][Target][MC] Fixed rule-of-three for RegisterTargetPassConfigCallback classes (PR #193470)

[James Henderson via llvm-commits]

https://github.com/jh7370 approved this pull request.

Code LGTM in latest version. The commit title still refers to MC and uses "classes" instead of "class", so please fix these before merging.

As @MaskRay noted, the problem I was trying to get you to see is that there is zero benefit in adding a defaulted destructor, because that's exactly what the compiler will generate. The rule of three doesn't really apply in the Archive and MC context that you were trying to apply it in.

https://github.com/llvm/llvm-project/pull/193470