[mb] Add presubmit checks

infra/mb/mb_config.pyl

 # Copyright 2016 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.
 
 {
   # This is a map of buildbot master names -> buildbot builder names ->
   # config names (where each config name is a key in the 'configs' dict,
   # below). MB uses this dict to look up which config to use for a given bot.
   # Bots are ordered by appearance on waterfall.
   'masters': {
@@ skipping 72 matching lines @@
     },
 
     'release_bot': {
       'mixins': ['release', 'static', 'goma'],
     },
 
     'release_trybot': {
       'mixins': ['release_bot', 'minimal_symbols', 'dcheck_always_on'],
     },
 
-    'shared': {
-      'gn_args': 'is_component_build=true',
-      'gyp_defines': 'component=shared_library',
-    },
+    #'shared': {
+    #  'gn_args': 'is_component_build=true',
+    #  'gyp_defines': 'component=shared_library',
+    #},
 
     'static': {
       'gn_args': 'is_component_build=false',
       'gyp_defines': 'component=static_library',
     },
 
     'swarming': {
       'gn_args': 'v8_test_isolation_mode="prepare"',
       'gyp_defines': 'test_isolation_mode=prepare',
     },
@@ skipping 23 matching lines @@
     'v8_snapshot_internal': {
       'gn_args': 'v8_use_external_startup_data=false',
       'gyp_defines': 'v8_use_external_startup_data=0',
     },
 
     'x64': {
       'gn_args': 'target_cpu="x64"',
       'gyp_defines': 'target_arch=x64',
     },
 
-    'x86': {
-      'gn_args': 'target_cpu="x86"',
-      'gyp_defines': 'target_arch=ia32',
-    },
+    #'x86': {
+    #  'gn_args': 'target_cpu="x86"',
+    #  'gyp_defines': 'target_arch=ia32',
+    #},
   },
 }