[SelectionDAG] Remove the code that handles SETCC with a scalar result type from...

[SelectionDAG] Remove the code that handles SETCC with a scalar result type from vector widening.

There's no such thing as a setcc with vector operands and scalar result. And if we're trying to widen the result we would have to already be looking at a vector result type.

So this patch renames the VSETCC function as the SETCC function and delete the original SETCC function.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@319799 91177308-0d34-0410-b5e6-96231b3b80d8