[llvm] [NFC][LLVM][DSE] Extract large member functions out of class definition (PR #162320)

[Rahul Joshi via llvm-commits]

jurahul wrote:

Thanks. What about the concerns of not being able to get a high level view easily without being distracted by impl details? That was my main motivation to do this, but I am not too tied to it. I guess for interface classes (which are in header files) we already follow this and keep the impl separate in .cpp files, this was applying the same to file local classes (impl classes).

https://github.com/llvm/llvm-project/pull/162320