[turbofan] Handle impossible types (Type::None()) in the backend.

src/compiler/verifier.cc

Index: src/compiler/verifier.cc
diff --git a/src/compiler/verifier.cc b/src/compiler/verifier.cc
index 46cd825ff970d59a95cb6bdecf5636f46745c02c..3a03a643ba9e1243f6a0e1fbc6de679e5f9cbbdc 100644
--- a/src/compiler/verifier.cc
+++ b/src/compiler/verifier.cc
@@ -946,6 +946,13 @@ void Verifier::Visitor::Check(Node* node) {
       // CheckUpperIs(node, to));
       break;
     }
+    case IrOpcode::kImpossibleToWord32:
+    case IrOpcode::kImpossibleToWord64:
+    case IrOpcode::kImpossibleToFloat32:
+    case IrOpcode::kImpossibleToFloat64:
+    case IrOpcode::kImpossibleToTagged:
+    case IrOpcode::kImpossibleToBit:
+      break;
 
     case IrOpcode::kCheckBounds:
       CheckValueInputIs(node, 0, Type::Any());