Removes stub from arm64 to fix build.

runtime/vm/stub_code_arm64.cc

 // Copyright (c) 2014, 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_ARM64)
 
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/compiler.h"
@@ skipping 33 matching lines @@
 void StubCode::GenerateCallStaticFunctionStub(Assembler* assembler) {
   UNIMPLEMENTED();
 }
 
 
 void StubCode::GenerateFixCallersTargetStub(Assembler* assembler) {
   UNIMPLEMENTED();
 }
 
 
-void StubCode::GenerateInstanceFunctionLookupStub(Assembler* assembler) {
-  UNIMPLEMENTED();
-}
-
-
 void StubCode::GenerateDeoptimizeLazyStub(Assembler* assembler) {
   UNIMPLEMENTED();
 }
 
 
 void StubCode::GenerateDeoptimizeStub(Assembler* assembler) {
   UNIMPLEMENTED();
 }
 
 
@@ skipping 171 matching lines @@
 
 
 void StubCode::GenerateOptimizedIdenticalWithNumberCheckStub(
     Assembler* assembler) {
   UNIMPLEMENTED();
 }
 
 }  // namespace dart
 
 #endif  // defined TARGET_ARCH_ARM64