[llvm] [MISched] Add statistics to quantify scheduling (PR #138090)

[David Green via llvm-commits]

davemgreen wrote:

A question about how this works - If you start with `A;B;C;D;E` and reorder it to `A;E;B;C;D`, does only 1 node count as in-order, or do 4? Is 4 nodes being inorder covered by #137981 (at least if they pick NodeOrder to remain in-order).

https://github.com/llvm/llvm-project/pull/138090