[runtime] Remove unused %NumberUnaryMinus runtime function.

src/runtime/runtime-numbers.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/runtime/runtime-utils.h"
 
 #include "src/arguments.h"
 #include "src/base/bits.h"
 #include "src/bootstrapper.h"
 #include "src/codegen.h"
@@ skipping 232 matching lines @@
 RUNTIME_FUNCTION(Runtime_NumberMul) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   return *isolate->factory()->NewNumber(x * y);
 }
 
 
-RUNTIME_FUNCTION(Runtime_NumberUnaryMinus) {
-  HandleScope scope(isolate);
-  DCHECK(args.length() == 1);
-
-  CONVERT_DOUBLE_ARG_CHECKED(x, 0);
-  return *isolate->factory()->NewNumber(-x);
-}
-
-
 RUNTIME_FUNCTION(Runtime_NumberDiv) {
   HandleScope scope(isolate);
   DCHECK(args.length() == 2);
 
   CONVERT_DOUBLE_ARG_CHECKED(x, 0);
   CONVERT_DOUBLE_ARG_CHECKED(y, 1);
   return *isolate->factory()->NewNumber(x / y);
 }
 
 
@@ skipping 205 matching lines @@
 }
 
 
 RUNTIME_FUNCTION(Runtime_GetRootNaN) {
   SealHandleScope shs(isolate);
   DCHECK(args.length() == 0);
   return isolate->heap()->nan_value();
 }
 }  // namespace internal
 }  // namespace v8