Update VM service to new isolate API

tests/standalone/standalone.status

 # Copyright (c) 2013, 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.
 
 # WARNING:
 # Tests using the multitest feature where failure is expected should *also* be
 # listed in tests/lib/analyzer/analyze_tests.status without the "standalone"
 # prefix.
 
 package/invalid_uri_test: Fail, OK # CompileTimeErrors intentionally
 
 [ $runtime == vm && $system == windows ]
 io/file_system_watcher_test: Pass, Timeout # Issue 13228
 io/platform_test: Pass, Fail # Issue 14399
 
 [ $runtime == vm ]
 package/package_isolate_test: Fail # Issue 12474
-vmservice/isolate_bad_class_test: Skip # Issue 14448
-vmservice/isolate_bad_object_test: Skip # Issue 14448
-vmservice/isolate_class_field_test: Skip # Issue 14448
-vmservice/isolate_class_test: Skip # Issue 14448
-vmservice/isolate_code_test: Skip # Issue 14448
-vmservice/isolate_echo_test: Skip # Issue 14448
-vmservice/isolate_function_test: Skip # Issue 14448
-vmservice/isolate_library_test: Skip # Issue 14448
-vmservice/isolate_list_test: Skip # Issue 14448
-vmservice/isolate_stacktrace_command_test: Skip # Issue 14448
-vmservice/multiple_isolate_list_test: Skip # Issue 14448
-vmservice/unknown_command_test: Skip # Issue 14448
-vmservice/unknown_isolate_command_test: Skip # Issue 14448
-
 
 [ $runtime == vm && $checked ]
 # These tests have type errors on purpose.
 io/process_invalid_arguments_test: Fail, OK
 io/directory_invalid_arguments_test: Fail, OK
 io/file_invalid_arguments_test: Fail, OK
 io/socket_invalid_arguments_test: Fail, OK
 io/stdout_bad_argument_test: Fail, OK
 # These test have type errors on purpose and take very long to run in
 # checked mode with no benefit. Skip.
@@ skipping 135 matching lines @@
 io/test_extension_fail_test: Fail
 io/dart_std_io_pipe_test: Fail
 io/file_read_special_device_test: Fail
 
 [ $compiler == none && $runtime == dartium && $unchecked ]
 assert_test: Fail # Issue 13719: Please triage this failure.
 
 [ $compiler == none && $runtime == dartium ]
 javascript_int_overflow_literal_test/01: Fail # Issue 13719: Please triage this failure.
 javascript_int_overflow_test: Fail # Issue 13719: Please triage this failure.