Enable causal stacktrace in kernel

tests/language/language_kernel.status

 # Copyright (c) 2016, 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.
 
 # These tests currently take too long. Remove when they are fixed.
 [ $compiler == dartk || $compiler == dartkp ]
 large_class_declaration_test: SkipSlow  # KernelVM Issue 28312
 
 ###############################################################################
 # Dartk Entries
@@ skipping 26 matching lines @@
 multiline_newline_test/03: CompileTimeError
 multiline_newline_test/04: MissingCompileTimeError
 multiline_newline_test/05: MissingCompileTimeError
 multiline_newline_test/06: MissingCompileTimeError
 regress_27617_test/1: MissingCompileTimeError
 type_variable_conflict2_test/02: MissingCompileTimeError
 vm/debug_break_enabled_vm_test/01: CompileTimeError
 vm/debug_break_enabled_vm_test/none: CompileTimeError
 vm/reflect_core_vm_test: CompileTimeError
 vm/regress_27201_test: CompileTimeError
-vm/regress_28325_test: RuntimeError  # Issue 28055.
+vm/regress_28325_test: Pass # Issue 28055. Passes by mistake.
 
 # dartk: JIT failures
 [ $compiler == dartk && $runtime == vm ]
 config_import_corelib_test: RuntimeError
 
 # dartk: precompilation failures
 [ $compiler == dartkp && $runtime == dart_precompiled ]
 config_import_corelib_test: RuntimeError
 not_enough_positional_arguments_test/01: DartkCompileTimeError # Issue 28590
 
@@ skipping 138 matching lines @@
 # dartk: JIT failures
 [ $compiler == dartk && $runtime == vm ]
 const_locals_test: RuntimeError
 constructor_named_arguments_test/01: Crash  # Dartk Issue 28301
 const_string_test: RuntimeError  # Dartk Issue 28306
 deferred_regression_28678_test: RuntimeError
 library_env_test/has_no_mirror_support: RuntimeError
 main_not_a_function_test/01: Crash
 redirecting_factory_reflection_test: RuntimeError
 
-# Casual async stack traces are not implemented for Kernel.
-vm/causal_async_exception_stack_test: RuntimeError
-vm/causal_async_exception_stack2_test: RuntimeError
-
 # dartk: JIT failures (debug)
 [ $compiler == dartk && $runtime == vm && $mode == debug ]
 not_enough_positional_arguments_test/02: Crash  # Dartk Issue 28301
 not_enough_positional_arguments_test/05: Crash  # Dartk Issue 28301
 
 # dartk: precompilation failures
 [ $compiler == dartkp && $runtime == dart_precompiled ]
 deferred_regression_28678_test: RuntimeError # Issue 28335
 enum_syntax_test/05: MissingCompileTimeError
 
@@ skipping 24 matching lines @@
 bad_raw_string_test/none: Skip # Issue 28680
 bad_raw_string_test/03: Skip # Issue 28680
 
 # Triaged checked mode failures
 [ ($compiler == dartk || $compiler == dartkp) && $checked ]
 language/regress_22728_test: Fail # Dartk Issue 28498
 
 # Slow (very slow!) during Gardening shift:
 [ $compiler == dartk && $runtime == vm && $mode == debug ]
 vm/optimized_stacktrace_test: Skip # Issue 28788