Fix the handling of exceptions from process start

runtime/bin/process_impl.dart

Index: runtime/bin/process_impl.dart
diff --git a/runtime/bin/process_impl.dart b/runtime/bin/process_impl.dart
index da7610f16d2d44257b2dda366fd6061aa532b7d5..98d72b4811ffc2f630c5209f487e6439854508dc 100644
--- a/runtime/bin/process_impl.dart
+++ b/runtime/bin/process_impl.dart
@@ -122,10 +122,10 @@ class _Process implements Process {
     if (_closed) {
       throw new ProcessException("Process closed");
     }
-    if (_in._id != 0) { _in.close(); }
-    if (_out._id != 0) { _out.close(); }
-    if (_err._id != 0) { _err.close(); }
-    if (_exitHandler._id != 0) { _exitHandler.close(); }
+    _in.close();
+    _out.close();
+    _err.close();
+    _exitHandler.close();
     _closed = true;
   }