Run generate_json_test again on mac, to investigate failure.

pkg/pkg.status

 # Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 # Don't run any test-like files that show up in packages directories. It
 # shouldn't be necessary to run "pub install" in these packages, but if you do
 # it shouldn't break the tests.
 */packages/*/*: Skip
 */*/packages/*/*: Skip
 */*/*/packages/*/*: Skip
@@ skipping 13 matching lines @@
 docgen/test/single_library_test: Skip # Way too slow
 docgen/test/typedef_test: Skip # Way too slow
 
 [ $runtime == vm ]
 docgen/test/only_lib_content_in_pkg_test: Fail, Timeout # Issue 17597
 
 [ $runtime == vm && ( $arch == simarm || $arch == simmips ) ]
 docgen/test/only_lib_content_in_pkg_test: Skip # slow
 docgen/test/typedef_test: Skip # slow
 
-[ $runtime == vm && $arch == ia32 && $mode == debug ]
+[ $runtime == vm && $arch == ia32 && $mode == debug && $system != macos ]
 docgen/test/generate_json_test: Skip # Issue 17602
 
 [ $compiler == dart2js ]
 collection/test/equality_test/01: Fail # Issue 1533
 collection/test/equality_test/02: Fail # Issue 1533
 collection/test/equality_test/03: Fail # Issue 1533
 collection/test/equality_test/04: Fail # Issue 1533
 collection/test/equality_test/05: Fail # Issue 1533
 collection/test/equality_test/none: Pass, Fail # Issue 14348
 third_party/angular_tests/browser_test: Pass, Slow # Large dart2js compile time
@@ skipping 338 matching lines @@
 collection/test/priority_queue_test: PubGetError
 collection/test/unmodifiable_collection_test: PubGetError
 collection/test/wrapper_test: PubGetError
 stack_trace/test/chain_test: PubGetError
 stack_trace/test/frame_test: PubGetError
 stack_trace/test/trace_test: PubGetError
 stack_trace/test/vm_test: PubGetError
 
 [ $runtime == ie9 ]
 polymer: Pass, Fail, Timeout # Issue 16717