Deprecate gfe2_reloadable_flag_quic_default_to_2_rttvar.

PiperOrigin-RevId: 344882968
Change-Id: Ib4e055688cc0c59ceee260145c4ff5c59edd04c8
diff --git a/quic/core/quic_sent_packet_manager.cc b/quic/core/quic_sent_packet_manager.cc
index 30ca57b..5927b14 100644
--- a/quic/core/quic_sent_packet_manager.cc
+++ b/quic/core/quic_sent_packet_manager.cc
@@ -1146,10 +1146,7 @@
   max_probe_packets_per_pto_ = 1;
   skip_packet_number_for_pto_ = true;
   first_pto_srtt_multiplier_ = 1.5;
-  if (GetQuicReloadableFlag(quic_default_to_2_rttvar)) {
-    QUIC_RELOADABLE_FLAG_COUNT(quic_default_to_2_rttvar);
-    pto_rttvar_multiplier_ = 2;
-  }
+  pto_rttvar_multiplier_ = 2;
 }
 
 void QuicSentPacketManager::StartExponentialBackoffAfterNthPto(