[clang-tools-extra] [clang-tidy] performance-unnecessary-copy-init: Add a hook... (PR #73921)

[Piotr Zegar via cfe-commits]

================
@@ -261,21 +262,27 @@ void UnnecessaryCopyInitialization::registerMatchers(MatchFinder *Finder) {
                      this);
 }
 
+UnnecessaryCopyInitialization::CheckContext::CheckContext(
----------------
PiotrZSL wrote:

I'm not a fan of this constructor, it should exist.
instead object of CheckContext should be created as:

```
CheckContext context{*NewVar, *BlockStmt, *OldVar, ...};
```

simply moving functionality of check into helper class isn't nice.
```

https://github.com/llvm/llvm-project/pull/73921