Since SERVER-52588, on FCV upgrade we create a 'timestamp' for the collections in configsvr's config.collections. The shard-local cache will be refreshed the first time it sees a new version with Epoch+Timestamp. This is not guaranteed to happen for all collections, unless they are referenced.

In order to facilitate the upgrade from 5.0 to 5.1, where SERVER-52847 will make the 'timestamp' required in IDL, we want to guarantee that upon finishing the upgrade to 5.0, no cached entries are left without timestamp anywhere.

This ticket is to ensure that the shard-local caches are refreshed after FCV upgrade to 5.0.

This can be accomplished by either:

• Doing FCV upgrade in a 2-phase commit manner (if we end up doing in)
• Issuing _flushRoutingTable({syncFromConfig:true} commands.