Bug 1695580 - Release WebSocketChannel::mTargetThread on main. r=necko-reviewers,dragana

When mTargetThread is WebSocketImpl it must be released on main since it
implements nsISupportsWeakReference, and clearing weak references is not
threadsafe.

Differential Revision: https://phabricator.services.mozilla.com/D109783

netwerk/protocol/websocket/WebSocketChannel.cpp

@@ -1181,6 +1181,8 @@ WebSocketChannel::~WebSocketChannel() {
 
   NS_ReleaseOnMainThread("WebSocketChannel::mLoadGroup", mLoadGroup.forget());
   NS_ReleaseOnMainThread("WebSocketChannel::mLoadInfo", mLoadInfo.forget());
+  NS_ReleaseOnMainThread("WebSocketChannel::mTargetThread",
+                         mTargetThread.forget());
   NS_ReleaseOnMainThread("WebSocketChannel::mService", mService.forget());
 }