TBR: Disable mirror matcher test for dart2js/csp.

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 52 matching lines @@
 analyzer_experimental/test/generated/ast_test: Fail, Slow # Issue 11230
 stack_trace/test/trace_test: Pass, Timeout # Issue 11645
 
 [ $compiler == dartc || $compiler == dartanalyzer || $compiler == dart2analyzer]
 # These tests are runtime negative but statically positive, so we skip
 # them in the analyzer.
 unittest/test/mock_regexp_negative_test: Skip
 unittest/test/mock_stepwise_negative_test: Skip
 
 [ $compiler == dart2js && $csp ]
+unittest/test/mirror_matchers_test: Skip # Issue 12151
 observe/test/observe_test: Fail # Issue 11970
 observe/test/path_observer_test: Fail  # Issue 11970
 mdv/test/binding_syntax_test: Fail # Issue 11970
 serialization/test/serialization_test: Fail # Issue 6490
 serialization/test/no_library_test: Fail # Issue 6490
 
 # This test cannot run under CSP because it is injecting a JavaScript polyfill
 mutation_observer: Skip
 
 [ $compiler == dart2js && $minified ]
@@ skipping 90 matching lines @@
 
 # Skip tests on the VM if the package depends on dart:html
 [ $runtime == vm ]
 custom_element: Skip
 mdv: Skip
 mutation_observer: Skip
 
 [ $runtime == safari || $runtime == chrome || $runtime == ie9 || $runtime == ff || $runtime == dartium || $runtime == drt ]
 docgen/test/single_library_test: Skip # Uses dart:io