Revert until Windows crash is debugged.

runtime/bin/socket_patch.dart

Index: runtime/bin/socket_patch.dart
diff --git a/runtime/bin/socket_patch.dart b/runtime/bin/socket_patch.dart
index d86a17c1d8de72491c92c29d068310286db63a87..f233a982789d4ad4d18f2c88aba3147a9118a9ea 100644
--- a/runtime/bin/socket_patch.dart
+++ b/runtime/bin/socket_patch.dart
@@ -837,6 +837,11 @@ class _SocketStreamConsumer extends StreamConsumer<List<int>> {
       if (offset < buffer.length) {
         if (!paused) {
           paused = true;
+          // TODO(ajohnsen): It would be nice to avoid this check.
+          // Some info: socket._write can emit an event, if it fails to write.
+          // If the user closes the socket in that event, stop() will be called
+          // before we get a change to pause.
+          if (subscription == null) return;
           subscription.pause();
         }
         socket._enableWriteEvent();
@@ -869,7 +874,6 @@ class _SocketStreamConsumer extends StreamConsumer<List<int>> {
     if (subscription == null) return;
     subscription.cancel();
     subscription = null;
-    paused = false;
     socket._disableWriteEvent();
   }
 }