Remove runtime 'dart_app' as it became identical to 'vm'.

tests/isolate/isolate.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.
 
-[ ($runtime == vm || $runtime == dart_precompiled || $runtime == dart_app) ]
+[ $runtime == vm || $runtime == dart_precompiled ]
 browser/*: SkipByDesign  # Browser specific tests
 isolate_stress_test: Skip # Issue 12588: Uses dart:html. This should be able to pass when we have wrapper-less tests.
 
-[ $runtime != vm || $mode == product ]
+[ $runtime != vm || $mode == product || $compiler == app_jit ]
 checked_test: Skip # Unsupported.
 
-[ ($runtime == vm || $runtime == dart_precompiled || $runtime == dart_app) && $arch == mips && $mode == debug ]
+[ ($runtime == vm || $runtime == dart_precompiled) && $arch == mips && $mode == debug ]
 mandel_isolate_test: Skip # Uses 600 MB Ram on our 1 GB test device.
 
-[ ($compiler == none || $compiler == precompiler || $compiler == dart2app || $compiler == dart2appjit) ]
+[ $compiler == none || $compiler == precompiler || $compiler == app_jit ]
 compile_time_error_test/01: Skip # Issue 12587
 ping_test: Skip           # Resolve test issues
 ping_pause_test: Skip     # Resolve test issues
 kill3_test: Pass, Fail    # Bad test: expects total message order
 
 message3_test/int32x4: Crash, Timeout # Issue 21818
 
 [ $compiler == dart2js && $runtime == safarimobilesim ]
 compile_time_error_test/none: Pass, Slow
 
@@ skipping 158 matching lines @@
 nested_spawn2_test: SkipByDesign
 nested_spawn_test: SkipByDesign
 raw_port_test: SkipByDesign
 request_reply_test: SkipByDesign
 spawn_function_custom_class_test: SkipByDesign
 spawn_function_test: SkipByDesign
 stacktrace_message_test: SkipByDesign
 static_function_test: SkipByDesign
 unresolved_ports_test: SkipByDesign
 
-[ $runtime == dart_precompiled || $runtime == dart_app ]
+[ $runtime == dart_precompiled || $compiler == app_jit ]
 count_test: Skip # Isolate.spawnUri
 cross_isolate_message_test: Skip # Isolate.spawnUri
 deferred_in_isolate2_test: Skip # Isolate.spawnUri
 deferred_in_isolate_test: Skip # Isolate.spawnUri
 deferred_in_isolate_test: Skip # Isolate.spawnUri
 error_at_spawnuri_test: Skip # Isolate.spawnUri
 error_exit_at_spawnuri_test: Skip # Isolate.spawnUri
 exit_at_spawnuri_test: Skip # Isolate.spawnUri
 illegal_msg_function_test: Skip # Isolate.spawnUri
 illegal_msg_mirror_test: Skip # Isolate.spawnUri
@@ skipping 24 matching lines @@
 
 [ $mode == product ]
 issue_24243_parent_isolate_test: Skip # Requires checked mode
 
 [ $hot_reload || $hot_reload_rollback ]
 function_send_test: Pass, Fail # Closure identity
 message3_test/fun: Pass, Fail # Closure identity
 deferred_in_isolate_test: Crash # Requires deferred libraries
 deferred_in_isolate2_test: Crash # Requires deferred libraries
 issue_21398_parent_isolate2_test: Crash # Requires deferred libraries