gfe-relnote: In QUIC, add probe timeout mode, which unifies TLP and RTO. Protected by gfe2_reloadable_flag_quic_enable_pto.

PTO mode is enabled on client side if gfe2_reloadable_flag_quic_enable_pto is true and client sends 1PTO or 2PTO. PTO mode is enabled on server side if gfe2_reloadable_flag_quic_enable_pto is true and server receives 1PTO or 2PTO from client.

Connection is closed after 7 or 8 PTO depending on connection option 7PTO or 8PTO, respectively.

PiperOrigin-RevId: 263574963
Change-Id: Id952a3e4640146c3fe72e3d6745cbac5ee16dcdc
diff --git a/quic/core/http/end_to_end_test.cc b/quic/core/http/end_to_end_test.cc
index d6c8486..4d7d1df 100644
--- a/quic/core/http/end_to_end_test.cc
+++ b/quic/core/http/end_to_end_test.cc
@@ -362,7 +362,9 @@
       copt.push_back(kTPCC);
     }
     copt.push_back(GetParam().priority_tag);
-
+    if (GetQuicReloadableFlag(quic_enable_pto)) {
+      copt.push_back(k2PTO);
+    }
     client_config_.SetConnectionOptionsToSend(copt);
 
     // Start the server first, because CreateQuicClient() attempts