Fix missing initialization of AccumulatorCaches in Eval::trace

Add a constructor to `AccumulatorCaches` instead of just calling
`clear(networks)` to prevent similar issues from appearing in the
future.

fixes https://github.com/official-stockfish/Stockfish/issues/5190

closes https://github.com/official-stockfish/Stockfish/pull/5191

No functional change

src/search.cpp

@@ -137,11 +137,11 @@ Search::Worker::Worker(SharedState&                    sharedState,
     // Unpack the SharedState struct into member variables
     thread_idx(thread_id),
     manager(std::move(sm)),
-    refreshTable(),
     options(sharedState.options),
     threads(sharedState.threads),
     tt(sharedState.tt),
-    networks(sharedState.networks) {
+    networks(sharedState.networks),
+    refreshTable(networks) {
     clear();
 }