[llvm] [GlobalISel] Refactor Combiner MatchData & Apply C++ Code Handling (PR #92239)

[Jay Foad via llvm-commits]

jayfoad wrote:

Awesome! Thanks for doing this so quickly.
```
unsigned SomeMatchData;
if (match(SomeMatchData))
  apply(SomeMatchData)
```
Do the match and apply functions get inlined into this?

https://github.com/llvm/llvm-project/pull/92239