[SelectionDAG] Remove unneeded vector resize from the end of FoldCons…

…tantArithmetic. NFC

There's an assert right before that makes sure the size already matches.
Earlier in this function's life, scalars and vectors shared more
code.

llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp

@@ -5150,9 +5150,6 @@ SDValue SelectionDAG::FoldConstantArithmetic(unsigned Opcode, const SDLoc &DL,
   assert(VT.getVectorNumElements() == Outputs.size() &&
          "Vector size mismatch!");
 
-  // We may have a vector type but a scalar result. Create a splat.
-  Outputs.resize(VT.getVectorNumElements(), Outputs.back());
-
   // Build a big vector out of the scalar elements we generated.
   return getBuildVector(VT, SDLoc(), Outputs);
 }