Fix release x64 build:

runtime/vm/stub_code_x64.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/globals.h"
 #if defined(TARGET_ARCH_X64)
 
 #include "vm/assembler.h"
 #include "vm/compiler.h"
 #include "vm/dart_entry.h"
@@ skipping 1198 matching lines @@
   if (FLAG_throw_on_javascript_int_overflow) {
     // The overflow check is more complex than implemented below.
     return;
   }
   ASSERT(num_args == 2);
   __ movq(RCX, Address(RSP, + 1 * kWordSize));  // Right
   __ movq(RAX, Address(RSP, + 2 * kWordSize));  // Left.
   __ movq(R12, RCX);
   __ orq(R12, RAX);
   __ testq(R12, Immediate(kSmiTagMask));
-#if defined(DEBUG)
-  const bool jump_length = Assembler::kFarJump;
-#else
-  const bool jump_length = Assembler::kNearJump;
-#endif
-  __ j(NOT_ZERO, not_smi_or_overflow, jump_length);
+  __ j(NOT_ZERO, not_smi_or_overflow);
   switch (kind) {
     case Token::kADD: {
       __ addq(RAX, RCX);
-      __ j(OVERFLOW, not_smi_or_overflow, jump_length);
+      __ j(OVERFLOW, not_smi_or_overflow);
       break;
     }
     case Token::kSUB: {
       __ subq(RAX, RCX);
-      __ j(OVERFLOW, not_smi_or_overflow, jump_length);
+      __ j(OVERFLOW, not_smi_or_overflow);
       break;
     }
     case Token::kEQ: {
       Label done, is_true;
       __ cmpq(RAX, RCX);
       __ j(EQUAL, &is_true, Assembler::kNearJump);
       __ LoadObject(RAX, Bool::False(), PP);
       __ jmp(&done, Assembler::kNearJump);
       __ Bind(&is_true);
       __ LoadObject(RAX, Bool::True(), PP);
@@ skipping 823 matching lines @@
 
   __ movq(left, Address(RSP, 2 * kWordSize));
   __ movq(right, Address(RSP, 1 * kWordSize));
   GenerateIdenticalWithNumberCheckStub(assembler, left, right);
   __ ret();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_X64