Return the correct port from Uri, when port is 0 and scheme is either http or https.

tests/co19/co19-analyzer2.status

 # Copyright (c) 2013, 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 == dart2analyzer ]
 # not clear: g([var foo = foo + 10]) is parameter 'foo' in the scope of its own initialzer?
 Language/06_Functions/2_Formal_Parameters_A02_t02: fail
 
 # not clear: null..[1](1)[2](2).foo(3, bar: 4)=5 - it seems that verything before =5 it not assignable
 Language/07_Classes/6_Constructors/1_Generative_Constructors_A04_t15: fail
@@ skipping 12 matching lines @@
 Language/12_Expressions/12_Instance_Creation/2_Const_A09_t03: fail
 
 # TBF: infinite look: class A {const A();final m = const A();}
 Language/12_Expressions/01_Constants_A17_t03: fail
 
 # analyzer issue https://code.google.com/p/dart/issues/detail?id=11534
 Language/15_Types/4_Interface_Types_A11_t01: Skip
 Language/15_Types/4_Interface_Types_A11_t02: Skip
 
 
-
+LibTest/core/Uri/decodeQueryComponent_A02_t01: fail # co19 Issue 591
 
 # co19 issue #380, Strings class has been removed
 LibTest/core/RegExp/Pattern_semantics/firstMatch_CharacterClassEscape_A03_t01: fail, OK
 LibTest/core/RegExp/Pattern_semantics/firstMatch_CharacterClassEscape_A04_t01: fail, OK
 
 # co19 issue #400, collection library reorg
 LibTest/core/String/String_class_A01_t01: fail, OK
 LibTest/core/String/concat_A01_t01: fail, OK
 LibTest/core/String/concat_A02_t01: fail, OK
 LibTest/core/String/hashCode_A01_t01: fail, OK
@@ skipping 133 matching lines @@
 LibTest/isolate/isolate_api/streamSpawnFunction_A02_t01: fail # co19-roll r576: Please triage this failure
 LibTest/isolate/IsolateSink/add_A01_t02: fail # co19-roll r546: Please triage this failure
 LibTest/isolate/IsolateSink/addError_A01_t01: fail # co19-roll r546: Please triage this failure
 LibTest/isolate/IsolateSink/addError_A01_t02: fail # co19-roll r546: Please triage this failure
 LibTest/isolate/IsolateSink/operator_equality_A01_t01: fail # co19-roll r546: Please triage this failure
 LibTest/isolate/IsolateStream/any_A02_t01: fail # co19-roll r546: Please triage this failure
 LibTest/isolate/IsolateStream/asBroadcastStream_A01_t01: fail # co19-roll r546: Please triage this failure
 LibTest/isolate/IsolateStream/contains_A01_t01: fail # co19-roll r546: Please triage this failure
 LibTest/isolate/IsolateStream/contains_A02_t01: fail # co19-roll r546: Please triage this failure
 LibTest/isolate/IsolateStream/isBroadcast_A01_t02: fail # co19-roll r546: Please triage this failure