[turbofan] Remove unused PlainPrimitiveToNumber operator.

src/compiler/typer.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/typer.h"
 
 #include "src/base/flags.h"
 #include "src/bootstrapper.h"
 #include "src/compilation-dependencies.h"
 #include "src/compiler/common-operator.h"
@@ skipping 1781 matching lines @@
 
 Type* Typer::Visitor::TypeNumberToUint32(Node* node) {
   return TypeUnaryOp(node, NumberToUint32);
 }
 
 
 Type* Typer::Visitor::TypeNumberIsHoleNaN(Node* node) {
   return Type::Boolean();
 }
 
-
-Type* Typer::Visitor::TypePlainPrimitiveToNumber(Node* node) {
-  return TypeUnaryOp(node, ToNumber);
-}
-
-
 // static
 Type* Typer::Visitor::ReferenceEqualTyper(Type* lhs, Type* rhs, Typer* t) {
   if (lhs->IsConstant() && rhs->Is(lhs)) {
     return t->singleton_true_;
   }
   return Type::Boolean();
 }
 
 
 Type* Typer::Visitor::TypeReferenceEqual(Node* node) {
@@ skipping 724 matching lines @@
   }
   if (Type::IsInteger(*value)) {
     return Type::Range(value->Number(), value->Number(), zone());
   }
   return Type::Constant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8