[llvm] [SelectionDAGBuilder] Remove NoNaNsFPMath uses (PR #169904)

[Matt Arsenault via llvm-commits]

================
@@ -14809,7 +14816,8 @@ SDValue DAGCombiner::foldSextSetcc(SDNode *N) {
   SDLoc DL(N);
 
   // Propagate fast-math-flags.
-  SelectionDAG::FlagInserter FlagsInserter(DAG, N0->getFlags());
+  SDNodeFlags Flags = N0->getFlags();
+  SelectionDAG::FlagInserter FlagsInserter(DAG, Flags);
----------------
arsenm wrote:

Is this still necessary? I don't understand having both Flags parameters, and using the FlagsInserter 

https://github.com/llvm/llvm-project/pull/169904