Make --abort_on_assertion_errors more selective.

tests/compiler/dart2js/dart2js.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.
 
 compile_with_empty_libraries_test: Fail # Issue 24223
 
 boolified_operator_test: Fail # Issue 8001
 
 # Don't mark these tests as failing. Instead, fix the errors/warnings that they
 # report or update the whitelist in the test-files to temporarily allow
@@ skipping 45 matching lines @@
 
 [ $unchecked ]
 exit_code_test: Skip # This tests requires checked mode.
 
 [ $checked ]
 analyze_dart2js_helpers_test: Pass, Slow
 analyze_dart2js_test: Pass, Slow
 analyze_unused_dart2js_test: Pass, Slow
 deferred_mirrors_test: Pass, Slow
 duplicate_library_test: Pass, Slow
-exit_code_test: Pass, Slow
+exit_code_test: Skip # Issue 25753, was: Pass, Slow
 import_mirrors_test: Slow, Pass
 interop_anonymous_unreachable_test: Pass, Slow
 mirror_final_field_inferrer2_test: Pass, Slow
 source_map_pub_build_validity_test: Pass, Slow
 uri_retention_test: Pass, Slow
 value_range_test: Pass, Slow
 
 [ $mode == debug ]
 check_elements_invariants_test: Skip # Slow and only needs to be run in one
                                      # configuration
@@ skipping 15 matching lines @@
 source_map_pub_build_validity_test: Pass, Slow
 
 # Don't mark these tests as failing. Instead, fix the errors/warnings that they
 # report or update the whitelist in the test-files to temporarily allow
 # digression.
 analyze_api_test: Pass, Slow # DON'T CHANGE THIS LINE -- SEE ABOVE.
 analyze_dart2js_test: Pass, Slow # DON'T CHANGE THIS LINE -- SEE ABOVE.
 
 [ $jscl || $runtime == drt || $runtime == dartium || $runtime == ff || $runtime == firefox || $runtime == chrome || $runtime == safari || $runtime == opera ]
 *: Skip # dart2js uses #import('dart:io'); and it is not self-hosted (yet).