[turbofan] Add binary operation hints for javascript operators.

src/compiler/type-hints.cc

+// Copyright 2015 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/type-hints.h"
+
+namespace v8 {
+namespace internal {
+namespace compiler {
+
+std::ostream& operator<<(std::ostream& os, BinaryOperationHints::Hint hint) {
+  switch (hint) {
+    case BinaryOperationHints::kNone:
+      return os << "None";
+    case BinaryOperationHints::kSignedSmall:
+      return os << "SignedSmall";
+    case BinaryOperationHints::kSigned32:
+      return os << "Signed32";
+    case BinaryOperationHints::kNumber:
+      return os << "Number";
+    case BinaryOperationHints::kString:
+      return os << "String";
+    case BinaryOperationHints::kAny:
+      return os << "Any";
+  }
+  UNREACHABLE();
+  return os;
+}
+
+
+std::ostream& operator<<(std::ostream& os, BinaryOperationHints hints) {
+  return os << hints.left() << "*" << hints.right() << "->" << hints.result();
+}
+
+}  // namespace compiler
+}  // namespace internal
+}  // namespace v8