fix: use concurrent hashmap instead of synchroniztion for recordcache

Signed-off-by: Lev Povolotsky <[email protected]>

hedera-node/hedera-app-spi/src/main/java/com/hedera/node/app/spi/state/ReadableKVStateBase.java

@@ -140,7 +140,6 @@ protected final void markRead(@NonNull K key, @Nullable V value) {
      * @return Whether it has been read
      */
     protected final boolean hasBeenRead(@NonNull K key) {
-        var keyExistence = readCache.get(key);
-        return keyExistence != null && keyExistence != marker;
+        return readCache.containsKey(key);
     }
 }