gfe-relnote: use QUIC_foo instead of ABSL_foo for mutex annotations in QUIC. Not flag protected. No behavior change.

This effectively reverts cr/266433516 and cr/266428140 (which were in turn reverts of cr/265958257 and cr/265940959) and then replaces the ABSL_ prefixes with QUIC_

PiperOrigin-RevId: 266445797
Change-Id: I369c0c929e5dc44a332635e695d526a2f91fa3f6
diff --git a/quic/test_tools/server_thread.h b/quic/test_tools/server_thread.h
index ffbce7f..d430297 100644
--- a/quic/test_tools/server_thread.h
+++ b/quic/test_tools/server_thread.h
@@ -73,13 +73,13 @@
   std::unique_ptr<QuicServer> server_;
   QuicSocketAddress address_;
   mutable QuicMutex port_lock_;
-  int port_ GUARDED_BY(port_lock_);
+  int port_ QUIC_GUARDED_BY(port_lock_);
 
   bool initialized_;
 
   QuicMutex scheduled_actions_lock_;
   QuicDeque<std::function<void()>> scheduled_actions_
-      GUARDED_BY(scheduled_actions_lock_);
+      QUIC_GUARDED_BY(scheduled_actions_lock_);
 };
 
 }  // namespace test