[builtins] Migrate Number.parseFloat to a TurboFan builtin.

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 <iomanip>
 
 #include "src/base/flags.h"
 #include "src/bootstrapper.h"
@@ skipping 1344 matching lines @@
         case kDateGetSeconds:
           return t->cache_.kJSDateSecondType;
         case kDateGetTime:
           return t->cache_.kJSDateValueType;
         // Number functions.
         case kNumberIsFinite:
         case kNumberIsInteger:
         case kNumberIsNaN:
         case kNumberIsSafeInteger:
           return Type::Boolean();
+        case kNumberParseFloat:
+          return Type::Number();
         case kNumberParseInt:
           return t->cache_.kIntegerOrMinusZeroOrNaN;
         case kNumberToString:
           return Type::String();
         // String functions.
         case kStringCharCodeAt:
           return Type::Union(Type::Range(0, kMaxUInt16, t->zone()), Type::NaN(),
                              t->zone());
         case kStringCharAt:
         case kStringConcat:
@@ skipping 374 matching lines @@
 Type* Typer::Visitor::TypeConstant(Handle<Object> value) {
   if (Type::IsInteger(*value)) {
     return Type::Range(value->Number(), value->Number(), zone());
   }
   return Type::NewConstant(value, zone());
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8