[llvm] [ConstantFolding] Constant fold nextafter and nexttoward (PR #168794)

[Matt Arsenault via llvm-commits]

================
@@ -0,0 +1,48 @@
+; RUN: true
----------------
arsenm wrote:

This is a bit exotic, but this is going to fail since it's not recognized as a test. Other places that read random other files usually have an Inputs subdirectory 

https://github.com/llvm/llvm-project/pull/168794