[SDAG] improve assert text for getSetCC type assumptions; NFC

Having identical text for these 2 conditions made it harder
to find the root problem for issue llvm#58994.

Author: rotateright

llvm/include/llvm/CodeGen/SelectionDAG.h

@@ -1119,9 +1119,9 @@ class SelectionDAG {
                    ISD::CondCode Cond, SDValue Chain = SDValue(),
                    bool IsSignaling = false) {
     assert(LHS.getValueType().isVector() == RHS.getValueType().isVector() &&
-           "Cannot compare scalars to vectors");
+           "Vector/scalar operand type mismatch for setcc");
     assert(LHS.getValueType().isVector() == VT.isVector() &&
-           "Cannot compare scalars to vectors");
+           "Vector/scalar result type mismatch for setcc");
     assert(Cond != ISD::SETCC_INVALID &&
            "Cannot create a setCC of an invalid node.");
     if (Chain)