Remove unused iossim setting from mac asan config

build/mac/asan.gyp

 # 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.
 
 {
    'targets': [
      {
        'target_name': 'asan_dynamic_runtime',
        'toolsets': ['target', 'host'],
        'type': 'none',
        'variables': {
          # Every target is going to depend on asan_dynamic_runtime, so allow
          # this one to depend on itself.
          'prune_self_dependency': 1,
          # Path is relative to this GYP file.
          'asan_rtl_mask_path':
              '../../third_party/llvm-build/Release+Asserts/lib/clang/*/lib/darwin',
          'asan_osx_dynamic':
              '<(asan_rtl_mask_path)/libclang_rt.asan_osx_dynamic.dylib',
-         'asan_iossim_dynamic':
-             '<(asan_rtl_mask_path)/libclang_rt.asan_iossim_dynamic.dylib',
        },
        'copies': [
          {
            'destination': '<(PRODUCT_DIR)',
            'files': [
              '<!(/bin/ls <(asan_osx_dynamic))',
            ],
          },
        ],
      },
    ],
 }