[turbofan] Float32Constant/Float64Constant cannot occur in JS level graph.

src/compiler/simplified-lowering.cc

Index: src/compiler/simplified-lowering.cc
diff --git a/src/compiler/simplified-lowering.cc b/src/compiler/simplified-lowering.cc
index 463bf030cd77b920840abfcde5107e0178e6d8b8..c7956b7bd240b72e2469034eea6b5759f07d41f8 100644
--- a/src/compiler/simplified-lowering.cc
+++ b/src/compiler/simplified-lowering.cc
@@ -1317,8 +1317,6 @@ class RepresentationSelector {
         return VisitLeaf(node, MachineRepresentation::kWord32);
       case IrOpcode::kInt64Constant:
         return VisitLeaf(node, MachineRepresentation::kWord64);
-      case IrOpcode::kFloat64Constant:
-        return VisitLeaf(node, MachineRepresentation::kFloat64);
       case IrOpcode::kExternalConstant:
         return VisitLeaf(node, MachineType::PointerRepresentation());
       case IrOpcode::kNumberConstant: