Add json fuzzer

test/fuzzer/fuzzer.isolate

 # 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': {
     'files': [
+      '<(PRODUCT_DIR)/json_fuzzer<(EXECUTABLE_SUFFIX)',
       '<(PRODUCT_DIR)/parser_fuzzer<(EXECUTABLE_SUFFIX)',
       '<(PRODUCT_DIR)/regexp_fuzzer<(EXECUTABLE_SUFFIX)',
       './fuzzer.status',
       './testcfg.py',
+      './json/',
       './parser/',
       './regexp/',
     ],
   },
   'includes': [
     '../../src/base.isolate',
     '../../tools/testrunner/testrunner.isolate',
   ],
 }