fix(forknet): do not load the memtries on dumper node (#12460)

The dumper node is an RPC and tracks all shards, it does not need to
load memtries

pytest/tests/mocknet/mirror.py

@@ -204,11 +204,11 @@ def _apply_stateless_config(args, node):
     """Applies configuration changes to the node for stateless validation,
     including changing config.json file and updating TCP buffer size at OS level."""
     # TODO: it should be possible to update multiple keys in one RPC call so we dont have to make multiple round trips
-    do_update_config(node, 'store.load_mem_tries_for_tracked_shards=true')
     # TODO: Enable saving witness after fixing the performance problems.
     do_update_config(node, 'save_latest_witnesses=false')
     if not node.want_state_dump:
         do_update_config(node, 'tracked_shards=[]')
+        do_update_config(node, 'store.load_mem_tries_for_tracked_shards=true')
     if not args.local_test:
         node.run_cmd(
             "sudo sysctl -w net.core.rmem_max=8388608 && sudo sysctl -w net.core.wmem_max=8388608 && sudo sysctl -w net.ipv4.tcp_rmem='4096 87380 8388608' && sudo sysctl -w net.ipv4.tcp_wmem='4096 16384 8388608' && sudo sysctl -w net.ipv4.tcp_slow_start_after_idle=0"