Rename gfe2_restart_flag_always_promote_chunk_if_coalesced_2 and remove "enabling_blocked_by".

Protected by FLAGS_gfe2_restart_flag_always_promote_chunk_if_coalesced_3.

PiperOrigin-RevId: 350136495
Change-Id: Icc7ad8036207dac743bc5d6c0f34c63bed16d48f

quic/core/quic_flags_list.h

diff --git a/quic/core/quic_flags_list.h b/quic/core/quic_flags_list.h
index 27383de..f64344c 100644
--- a/quic/core/quic_flags_list.h
+++ b/quic/core/quic_flags_list.h
@@ -1,4 +1,4 @@
-// Copyright (c) 2020 The Chromium Authors. All rights reserved.
+// Copyright (c) 2021 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.