[inspector] don't use String16 in inspector test runner

test/inspector/inspector.gyp

 # 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.
 
 {
   'variables': {
     'v8_code': 1,
     'inspector_protocol_sources': [
       'inspector-impl.cc',
       'inspector-impl.h',
       'inspector-test.cc',
       'task-runner.cc',
       'task-runner.h',
     ],
   },
   'includes': ['../../gypfiles/toolchain.gypi', '../../gypfiles/features.gypi'],
   'targets': [
     {
       'target_name': 'inspector-test',
       'type': 'executable',
       'dependencies': [
         '../../src/v8.gyp:v8_libplatform',
+        '../../src/v8.gyp:v8',
       ],
       'include_dirs': [
         '../..',
       ],
       'sources': [
         '<@(inspector_protocol_sources)',
       ],
       'conditions': [
         ['component=="shared_library"', {
           # inspector-test can't be built against a shared library, so we
           # need to depend on the underlying static target in that case.
           'dependencies': ['../../src/v8.gyp:v8_maybe_snapshot'],
         }, {
           'dependencies': ['../../src/v8.gyp:v8'],
         }],
       ],
     },
   ],
 }