Bug 261345

ipc/restrictedendpoints/deny-access-webPush.html is a flaky crash: ``` Thread 0 Crashed:: Dispatch queue: com.apple.main-thread 0 com.apple.WebKit 0x12f52383c IPC::Decoder::buffer() const 1 com.apple.WebKit 0x131d54c2c WebKit::IPCTestingAPI::jsResultFromReplyDecoder(JSC::JSGlobalObject*, IPC::MessageName, IPC::Decoder&) 2 com.apple.WebKit 0x131d6f788 WebKit::IPCTestingAPI::sendMessageWithJSArguments(IPC::Connection&, OpaqueJSContext const*, unsigned long, OpaqueJSValue const* const*, OpaqueJSValue const**)::$_20::operator()(IPC::Decoder*) const 3 com.apple.WebKit 0x131d6f654 WTF::Detail::CallableWrapper<WebKit::IPCTestingAPI::sendMessageWithJSArguments(IPC::Connection&, OpaqueJSContext const*, unsigned long, OpaqueJSValue const* const*, OpaqueJSValue const**)::$_20, void, IPC::Decoder*>::call(IPC::Decoder*) 4 com.apple.WebKit 0x130d950c4 WTF::Function<void (IPC::Decoder*)>::operator()(IPC::Decoder*) const 5 com.apple.WebKit 0x130d7aee4 WTF::CompletionHandler<void (IPC::Decoder*)>::operator()(IPC::Decoder*) 6 com.apple.WebKit 0x13264188c IPC::Connection::cancelAsyncReplyHandlers() 7 com.apple.WebKit 0x132642a4c IPC::Connection::invalidate() 8 com.apple.WebKit 0x131b1c110 WebKit::NetworkProcessConnection::~NetworkProcessConnection() 9 com.apple.WebKit 0x131b1c244 WebKit::NetworkProcessConnection::~NetworkProcessConnection() 10 com.apple.WebKit 0x131b1c274 WebKit::NetworkProcessConnection::~NetworkProcessConnection() ```