Gardening: Update status for flaky optimized_stacktrace_test

tests/language/language.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.
 
 # This directory contains tests that are intended to show the
 # current state of the language.
 
 [ $compiler == none || $compiler == app_jit ]
 null_is_bottom_test/22: RuntimeError # Issue 28025
 null_is_bottom_test/34: RuntimeError # Issue 28025
@@ skipping 317 matching lines @@
 assert_initializer_test/*: MissingCompileTimeError, OK  # asserts shouldn't fail in unchecked mode.
 assert_initializer_test/none: pass
 
 [$runtime == vm && $compiler == none && $checked]
 # The VM doesn't enforce that potentially const expressions are actually
 # const expressions when the constructor is called with `const`.
 assert_initializer_test/4*: MissingCompileTimeError # Issue 392.
 
 [$runtime == vm && $compiler == none]
 duplicate_part_test/01: MissingCompileTimeError # Issue 27516
+vm/optimized_stacktrace_test: Pass, Crash # Issue 28276
 
 [$compiler == dart2analyzer]
 vm/regress_27201_test: SkipByDesign # Loads bad library, so will always crash.
 config_import_corelib_test: StaticWarning, OK
 
 null_bottom_test/none: StaticWarning, CompileTimeError # Issue 28025
 null_bottom_test/01: Pass, CompileTimeError # Issue 28025
 null_bottom_test/02: Pass, CompileTimeError # Issue 28025
 null_bottom_test/03: Pass, CompileTimeError # Issue 28025
 
 # Issue #28236
 async_await_test: StaticWarning
 async_star_pause_test: StaticWarning
 async_star_test: StaticWarning
 regress_18535_test: StaticWarning
 
 [ $runtime == dart_precompiled || $runtime == vm || $runtime == dartium]
 null_bottom_test/none: RuntimeError # Issue 28025
 null_bottom_test/01: RuntimeError # Issue 28025
 null_bottom_test/02: RuntimeError # Issue 28025