[turbofan] Fix typo in IrOpcode::Mnemonic.

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.
 
 {
   'variables': {
     'v8_code': 1,
   },
   'includes': ['../../build/toolchain.gypi', '../../build/features.gypi'],
   'targets': [
@@ skipping 42 matching lines @@
         'compiler/js-builtin-reducer-unittest.cc',
         'compiler/js-operator-unittest.cc',
         'compiler/js-typed-lowering-unittest.cc',
         'compiler/load-elimination-unittest.cc',
         'compiler/machine-operator-reducer-unittest.cc',
         'compiler/machine-operator-unittest.cc',
         'compiler/move-optimizer-unittest.cc',
         'compiler/node-matchers-unittest.cc',
         'compiler/node-test-utils.cc',
         'compiler/node-test-utils.h',
+        'compiler/opcodes-unittest.cc',
         'compiler/register-allocator-unittest.cc',
         'compiler/select-lowering-unittest.cc',
         'compiler/simplified-operator-reducer-unittest.cc',
         'compiler/simplified-operator-unittest.cc',
         'compiler/value-numbering-reducer-unittest.cc',
         'compiler/zone-pool-unittest.cc',
         'libplatform/default-platform-unittest.cc',
         'libplatform/task-queue-unittest.cc',
         'libplatform/worker-thread-unittest.cc',
         'heap/gc-idle-time-handler-unittest.cc',
@@ skipping 58 matching lines @@
           'direct_dependent_settings': {
             'cflags!': [
               '-pedantic',
             ],
           },
         }],
       ],
     },
   ],
 }