This issue was found when SERVER-77184 was committed and it generated a hot BF in noPassthrough suites on query_stats_collect_on_mongos.js. 

 For this mongos query, when setEndOfOpMetrics() is called from ClusterFind::runQueryWithoutRetrying, the queryStats key hash is set on debug. But when we run a getMore to exhaust the cursor, ClusterFind::runGetMore calls setEndOfOpMetrics() and the key hash is actually _not set at that point. So with my commit, the executimeTime doesn't get recorded/updated.

The current fix is to just return at the top of query_stats_collect_on_mongos.js, however this ticket should address why the hash isn't persisted through the setEndOfOpMetrics() call in ClusterFind::runGetMore()