Make event-handlers edge-triggered and move socket-state to Dart.

tests/standalone/io/http_no_reason_phrase_test.dart

Index: tests/standalone/io/http_no_reason_phrase_test.dart
diff --git a/tests/standalone/io/http_no_reason_phrase_test.dart b/tests/standalone/io/http_no_reason_phrase_test.dart
index 9db6a643a4b83e3b2d7e2c2b46ee345e9d859f8b..9312cd4a164a3fd98c3703e078bafc9dd413b2cd 100644
--- a/tests/standalone/io/http_no_reason_phrase_test.dart
+++ b/tests/standalone/io/http_no_reason_phrase_test.dart
@@ -17,6 +17,7 @@ void missingReasonPhrase(int statusCode, bool includeSpace) {
   var client = new HttpClient();
   ServerSocket.bind("127.0.0.1", 0).then((server) {
      server.listen((client) {
+        client.listen(null);
         if (includeSpace) {
           client.write("HTTP/1.1 $statusCode \r\n\r\n");
         } else {
@@ -29,6 +30,7 @@ void missingReasonPhrase(int statusCode, bool includeSpace) {
         .then((response) {
           Expect.equals(statusCode, response.statusCode);
           Expect.equals("", response.reasonPhrase);
+          return response.drain();
         })
         .whenComplete(() => server.close());
   });