Add unittests to keep InstanceType lists in sync

test/unittests/unittests.gyp

 # 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.
 
 # The sources are kept automatically in sync with BUILD.gn.
 
 {
   'variables': {
     'v8_code': 1,
     'unittests_sources': [  ### gcmole(all) ###
@@ skipping 100 matching lines @@
       'libplatform/worker-thread-unittest.cc',
       'heap/bitmap-unittest.cc',
       'heap/gc-idle-time-handler-unittest.cc',
       'heap/gc-tracer-unittest.cc',
       'heap/marking-unittest.cc',
       'heap/memory-reducer-unittest.cc',
       'heap/heap-unittest.cc',
       'heap/scavenge-job-unittest.cc',
       'heap/slot-set-unittest.cc',
       'locked-queue-unittest.cc',
+      'object-unittest.cc',
       'register-configuration-unittest.cc',
       'run-all-unittests.cc',
       'source-position-table-unittest.cc',
       'test-utils.h',
       'test-utils.cc',
       'unicode-unittest.cc',
       'value-serializer-unittest.cc',
       'zone/segmentpool-unittest.cc',
       'zone/zone-chunk-list-unittest.cc',
       'wasm/asm-types-unittest.cc',
@@ skipping 141 matching lines @@
             '../../gypfiles/isolate.gypi',
           ],
           'sources': [
             'unittests.isolate',
           ],
         },
       ],
     }],
   ],
 }