New implementation of {,Linked}Hash{Set,Map}.

tests/co19/co19-dart2dart.status

Index: tests/co19/co19-dart2dart.status
diff --git a/tests/co19/co19-dart2dart.status b/tests/co19/co19-dart2dart.status
index 4993c008430a3eb46d4292cb5f05b9dd2de50e2e..7e33a01ad2b6573c9d3c166577fc5ed36c55e61b 100644
--- a/tests/co19/co19-dart2dart.status
+++ b/tests/co19/co19-dart2dart.status
@@ -655,3 +655,21 @@ LibTest/core/Queue/removeLast_A01_t01: Fail # Moved collection classes from core
 LibTest/core/Queue/removeLast_A02_t01: Fail # Moved collection classes from core to collection. co19 issue 371.
 LibTest/core/Set/Set.from_A01_t01: Fail # Moved collection classes from core to collection. co19 issue 371.
 Language/14_Types/4_Interface_Types_A08_t06: Fail # Moved collection classes from core to collection. co19 issue 371.
+
+# Doesn't expect null to be allowed in Set or Map keys (issue 377).
+LibTest/core/Map/containsKey_A01_t02: Fail
+LibTest/core/Map/operator_subscript_A01_t02: Fail
+LibTest/core/Map/operator_subscripted_assignment_A01_t02: Fail
+LibTest/core/Map/remove_A01_t02: Fail
+LibTest/core/Set/add_A01_t02: Fail
+LibTest/core/Set/addAll_A01_t02: Fail
+LibTest/core/Set/contains_A01_t02: Fail
+LibTest/core/Set/containsAll_A01_t02: Fail
+LibTest/core/Set/intersection_A03_t01: Fail
+LibTest/core/Set/isSubsetOf_A01_t02: Fail
+LibTest/core/Set/remove_A01_t02: Fail
+LibTest/core/Set/removeAll_A01_t02: Fail
+
+# Doesn't expect concurrent modification error (issue 376).
+LibTest/core/Map/forEach_A01_t07: Fail
+LibTest/core/Map/putIfAbsent_A01_t02: Fail