When creating WiredTigerCursors, we construct the entire configuration string and pass that to WiredTigerSessionCache::getCachedCursor. The majority of normal cursors utilize the session cache, and the implementation of getCachedCursor doesn't use the configuration string if a cached cursor is found.

Since cursor creation is in a hot path, we should first check the cache if a cursor is found, and only construct the configuration string for a new cursor when one isn't already open.