Mark analyzer/test/src/task/strong/front_end_inference_test as slow on checked VM.

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 63 matching lines @@
 front_end/*: SkipByDesign
 
 [ $runtime == vm && $mode == debug ]
 analysis_server/test/completion_test: Pass, Slow
 
 [ $runtime == vm && $checked ]
 analysis_server/test/completion_test: Pass, Slow
 analysis_server/test/services/correction/fix_test: Pass, Slow
 analysis_server/test/socket_server_test: Skip # Pass, Slow
 analyzer/test/src/summary/resynthesize_ast_test: Pass, Slow
+analyzer/test/src/task/strong/front_end_inference_test: Pass, Slow
 
 [ $runtime == vm && $checked && $system == windows ]
 front_end/tool/perf_test: Slow, Pass
 
 [ $runtime == vm && $use_sdk ]
 front_end/test/fasta/*: Skip # Issue 28629
 
 [ $runtime == vm && $use_sdk == false ]
 front_end/test/incremental_kernel_generator_test: Skip # Issue 28698
 front_end/test/incremental_resolved_ast_generator_test: Skip # Issue 28698
@@ skipping 111 matching lines @@
 
 [ $runtime == dart_precompiled ]
 *: SkipByDesign # The pkg test framework imports dart:mirrors.
 
 [ $compiler == none ]
 kernel/test/closures_test: Fail
 
 [ $runtime == vm && $system == windows ]
 analyzer_cli/test/driver_test: Pass, Slow
 analyzer/test/src/task/strong/checker_test: Pass, Slow