Revert "Signal handling."

tests/standalone/io/signals_test.dart

-// 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.
-
-import "dart:io";
-
-import "package:expect/expect.dart";
-import "package:async_helper/async_helper.dart";
-
-void testSignals(int usr1Expect,
-                 int usr2Expect,
-                 [int usr1Send,
-                  int usr2Send,
-                  bool shouldFail = false]) {
-  if (usr1Send == null) usr1Send = usr1Expect;
-  if (usr2Send == null) usr2Send = usr2Expect;
-  asyncStart();
-  Process.start(Platform.executable,
-      [Platform.script.resolve('signals_test_script.dart').toFilePath(),
-       usr1Expect.toString(),
-       usr2Expect.toString()])
-    .then((process) {
-      process.stdin.close();
-      process.stderr.drain();
-      int v = 0;
-      process.stdout.listen((out) {
-        // Send as many signals as 'ready\n' received on stdout
-        int count = out.where((c) => c == '\n'.codeUnitAt(0)).length;
-        for (int i = 0; i < count; i++) {
-          if (v < usr1Send) {
-            process.kill(ProcessSignal.SIGUSR1);
-          } else if (v < usr1Send + usr2Send) {
-            process.kill(ProcessSignal.SIGUSR2);
-          }
-          v++;
-        }
-      });
-      process.exitCode.then((exitCode) {
-        Expect.equals(shouldFail, exitCode != 0);
-        asyncEnd();
-      });
-    });
-}
-
-
-void testListenCancel() {
-  for (int i = 0; i < 10; i++) {
-    ProcessSignal.SIGUSR1.watch().listen(null).cancel();
-  }
-}
-
-void main() {
-  testListenCancel();
-  if (Platform.isWindows) return;
-  testSignals(0, 0);
-  testSignals(1, 0);
-  testSignals(0, 1);
-  testSignals(1, 1);
-  testSignals(10, 10);
-  testSignals(10, 1);
-  testSignals(1, 10);
-  testSignals(1, 0, 0, 1, true);
-  testSignals(0, 1, 1, 0, true);
-}