Update jsshell to 50.0

tests/corelib/corelib.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.
 
 [ $compiler == none && ($runtime == drt || $runtime == dartium) ]
 bool_from_environment2_test: Skip
 bool_from_environment_test: Skip
 from_environment_const_type_test: Skip
 from_environment_const_type_undefined_test: Skip
 int_from_environment2_test: Skip
@@ skipping 104 matching lines @@
 [ $compiler == dart2js && $runtime == safarimobilesim ]
 list_test/01: Fail # Safari bug: Array(-2) seen as dead code.
 string_trimlr_test/none: Fail
 
 [ $compiler == dart2js && $runtime == ie10 ]
 string_case_test/01: Fail, OK  # Bug in IE.
 string_case_test/02: Fail, OK  # Bug in IE.
 
 [ $compiler == dart2js && ($runtime == ff || $runtime == jsshell) ]
 string_case_test/01: Fail, OK  # Bug in Firefox.
+list_test/none: Fail # Issue 28014
+list_test/01: Fail # Issue 28014
 
 [ $compiler == dart2js && $runtime == dartium ]
 string_case_test/02: Fail, OK  # Bug in dartium version of V8.
 string_case_test/03: Fail, OK  # Bug in dartium version of V8.
 
 # Analyzer's implementation of fromEnvironment assumes that undefined
 # environment variables have an unspecified value (rather than being
 # null) because it is expected that the user will supply a value when
 # the code is run.  This means that it produces slightly different
 # error messages than the VM and Dart2js.
@@ skipping 69 matching lines @@
 package_resource_test: Skip # Resolve URI not supported yet in product mode.
 file_resource_test: Skip # Resolve URI not supported yet in product mode.
 http_resource_test: Skip # Resolve URI not supported yet in product mode.
 
 [ $arch == simdbc || $arch == simdbc64 ]
 regexp/stack-overflow_test: RuntimeError, OK # Smaller limit with irregex interpreter
 
 [ $hot_reload || $hot_reload_rollback ]
 big_integer_parsed_mul_div_vm_test: Pass, Slow # Slow.