[llvm] [Inline][Cloning] Defer constant propagation after phi-nodes resolution (PR #87963)

[Danila Malyutin via llvm-commits]

danilaml wrote:

I've noticed that before this PR, certain calls were simplified-away and now they are not because of
```cpp
      // Skip over non-intrinsic callsites, we don't want to remove any nodes
      // from the CGSCC.
      CallBase *CB = dyn_cast<CallBase>(NewI);
      if (CB && CB->getCalledFunction() &&
          !CB->getCalledFunction()->isIntrinsic())
        continue;
```

I'm not clear if this check is still required. And if it is, was the fact that it was missing in CloneBLock before a bug? Shouldn't it still be added there, since ConstantFold can still eliminate some non-intrinsic calls (i.e. some math functions)? It was added by @majnemer in 5554edabef3814395360c37e9854fa4aa7b1731e

https://github.com/llvm/llvm-project/pull/87963