[llvm] [VFABI] Improve VFABI unit tests (PR #73907)

[Paul Walker via llvm-commits]

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@@ -96,22 +96,23 @@ struct VFShape {
 
   // Retrieve the VFShape that can be used to map a (scalar) function to itself,
   // with VF = 1.
-  static VFShape getScalarShape(const CallInst &CI) {
-    return VFShape::get(CI, ElementCount::getFixed(1),
+  static VFShape getScalarShape(const FunctionType *FTy) {
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paulwalker-arm wrote:

I think it's perhaps worth breaking this (CallInst -> FunctionType) refactoring into a separate NFCish patch?

https://github.com/llvm/llvm-project/pull/73907