Increase HTTP/2 connection expiration test's timeouts (#40015)

Author: alnikola

src/libraries/System.Net.Http/tests/FunctionalTests/SocketsHttpHandlerTest.cs

@@ -2131,7 +2131,7 @@ public async Task Http2_MultipleConnectionsEnabled_IdleConnectionTimeoutExpired_
             const int MaxConcurrentStreams = 2;
             using Http2LoopbackServer server = Http2LoopbackServer.CreateServer();
             using SocketsHttpHandler handler = CreateHandler();
-            handler.PooledConnectionIdleTimeout = TimeSpan.FromSeconds(5);
+            handler.PooledConnectionIdleTimeout = TimeSpan.FromSeconds(10);
             using (HttpClient client = CreateHttpClient(handler))
             {
                 server.AllowMultipleConnections = true;
@@ -2142,7 +2142,7 @@ public async Task Http2_MultipleConnectionsEnabled_IdleConnectionTimeoutExpired_
                 Assert.Equal(MaxConcurrentStreams, acceptedStreamIds.Count);
 
                 List<Task<HttpResponseMessage>> connection1SendTasks = new List<Task<HttpResponseMessage>>();
-                Http2LoopbackConnection connection1 = await PrepareConnection(server, client, MaxConcurrentStreams, readTimeout: 10).ConfigureAwait(false);
+                Http2LoopbackConnection connection1 = await PrepareConnection(server, client, MaxConcurrentStreams, readTimeout: 15).ConfigureAwait(false);
                 AcquireAllStreamSlots(server, client, connection1SendTasks, MaxConcurrentStreams);
                 int handledRequests1 = (await HandleAllPendingRequests(connection1, MaxConcurrentStreams).ConfigureAwait(false)).Count;