Let `Isolate.errors` close on isolate exit.

tests/isolate/isolate_errors_test.dart

+// 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.
+
+library isolate_errors;
+
+import "dart:isolate";
+import "dart:async";
+import "package:async_helper/async_helper.dart";
+import "package:expect/expect.dart";
+
+isomain(arg) {
+  if (arg is SendPort) {
+    RawReceivePort wait = new RawReceivePort();
+    wait.handler = (message) {
+      wait.close();
+      isomain(message);
+    };
+    arg.send(wait.sendPort);
+  } else {
+    throw new ArgumentError(arg);
+  }
+}
+
+manyErrorsMain(int count) {
+  for (int i = 0; i < count; i++) {
+    Timer.run(() { throw "test#$i"; });
+  }
+}
+
+main(){
+  asyncStart();
+  {
+    asyncStart();
+    Isolate.spawn(isomain, "test-1", paused: true).then((Isolate i) {
+      var errors = [];
+      i.errors.listen(null,
+        onError: (e, s) {
+          errors.add(e.toString().contains("test-1"));
+        },
+        onDone: () {
+          Expect.listEquals([true], errors);
+          asyncEnd();
+        });
+      i.resume(i.pauseCapability);
+    });
+  }
+
+  {
+    asyncStart();
+    var messageReceived = new Completer();
+    var p = new RawReceivePort()..handler = messageReceived.complete;
+    Isolate.spawn(isomain, p.sendPort).then((i) {
+      messageReceived.future.then((port) {
+        p.close();
+        // Isolate has started and is waiting for response.
+        var errors = [];
+        i.errors.listen(null,
+          onError: (e, s) {
+            errors.add(e.toString().contains("test-2"));
+          },
+          onDone: () {
+            Expect.listEquals([true], errors);
+            asyncEnd();
+          });
+        port.send("test-2");
+      });
+    });
+  }
+
+  // {

[floitsch, 2016/12/07 16:12:00]

Reenable or remove?

+  //   asyncStart();
+  //   Isolate.spawn(manyErrorsMain, 5,
+  //                 paused: true, errorsAreFatal: false).then((i) {
+  //     var errors = [];
+  //     i.errors.listen(null,
+  //       onError: (e, s) {
+  //         print(e);
+  //         errors.add(e.toString().contains("test#${errors.length}"));
+  //       },
+  //       onDone: () {
+  //         print("done?");
+  //         Expect.listEquals([true, true, true, true, true], errors);
+  //         asyncEnd();
+  //       });
+  //     i.resume(i.pauseCapability);
+  //   });
+  // }
+
+  asyncEnd();
+}