Deprecate gfe2_reloadable_flag_quic_use_common_stream_check

gfe-relnote: n/a (Flag deprecation)
PiperOrigin-RevId: 291718830
Change-Id: I7f68290ab18e922e6373d87209f31d15741715c7

quic/core/http/quic_server_session_base.cc

diff --git a/quic/core/http/quic_server_session_base.cc b/quic/core/http/quic_server_session_base.cc
index 68d4c12..f52c19d 100644
--- a/quic/core/http/quic_server_session_base.cc
+++ b/quic/core/http/quic_server_session_base.cc
@@ -236,16 +236,6 @@
     return false;
   }
 
-  if (!GetQuicReloadableFlag(quic_use_common_stream_check) &&
-      !VersionHasIetfQuicFrames(transport_version())) {
-    if (GetNumOpenOutgoingStreams() >=
-        stream_id_manager().max_open_outgoing_streams()) {
-      QUIC_VLOG(1) << "No more streams should be created. "
-                   << "Already " << GetNumOpenOutgoingStreams() << " open.";
-      return false;
-    }
-  }
-  QUIC_RELOADABLE_FLAG_COUNT(quic_use_common_stream_check);
   return CanOpenNextOutgoingUnidirectionalStream();
 }