[turbofan] Use PlainPrimitiveToNumber whenever possible.

test/unittests/compiler/js-typed-lowering-unittest.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/access-builder.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-operator.h"
 #include "src/compiler/js-typed-lowering.h"
 #include "src/compiler/machine-operator.h"
 #include "src/compiler/node-properties-inl.h"
@@ skipping 354 matching lines @@
 
 
 TEST_F(JSTypedLoweringTest, JSToNumberWithPlainPrimitive) {
   Node* const input = Parameter(Type::PlainPrimitive(), 0);
   Node* const context = Parameter(Type::Any(), 1);
   Node* const effect = graph()->start();
   Node* const control = graph()->start();
   Reduction r = Reduce(graph()->NewNode(javascript()->ToNumber(), input,
                                         context, effect, control));
   ASSERT_TRUE(r.Changed());
-  EXPECT_THAT(r.replacement(), IsToNumber(input, IsNumberConstant(BitEq(0.0)),
-                                          graph()->start(), control));
+  EXPECT_THAT(r.replacement(), IsPlainPrimitiveToNumber(input));
 }
 
 
 // -----------------------------------------------------------------------------
 // JSStrictEqual
 
 
 TEST_F(JSTypedLoweringTest, JSStrictEqualWithTheHole) {
   Node* const the_hole = HeapConstant(factory()->the_hole_value());
   Node* const context = UndefinedConstant();
@@ skipping 412 matching lines @@
           IsStoreElement(
               access, IsIntPtrConstant(bit_cast<intptr_t>(&backing_store[0])),
               key, value, effect, control));
     }
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8