http3: fix memory leak in stream state tracking (#4523)

* fix(http3): handle streamStateSendAndReceiveClosed in onStreamStateChange

Signed-off-by: George MacRorie <me@georgemac.com>

* refactor(http3): adjust stateTrackingStream to operate over streamClearer and errorSetter

* test(http3): remove duplicate test case

* chore(http3): rename test spies to be mocks

---------

Signed-off-by: George MacRorie <me@georgemac.com>

http3/datagram_test.go

@@ -54,7 +54,7 @@ var _ = Describe("Datagrams", func() {
 		dg := newDatagrammer(nil)
 		dg.enqueue([]byte("foo"))
 		testErr := errors.New("test error")
-		Expect(dg.SetReceiveError(testErr)).To(BeFalse())
+		dg.SetReceiveError(testErr)
 		dg.enqueue([]byte("bar"))
 		data, err := dg.Receive(context.Background())
 		Expect(err).ToNot(HaveOccurred())