Several test suites use the ShardedClusterFixture to set up a sharded cluster before running specific tests, like for example sharding_jscore_passthrough. In the setup code the internal ReplicaSetFixture setup function is being called, and here the multiversion scenario is being considered, effectively running the setFeatureCompatibilityVersion command immediately after starting the node. This is done in case we want to set up a mixed binaries replica set, which works fine in the ReplicaSetFixture, but, it is problematic for a sharded cluster because it implies that the setFeatureCompatibilityVersion command is going to be called directly in a shard, which is not a valid use case.

The purpose of this ticket is to properly set up a sharded cluster with multiversion binaries. We could for example change the ShardedClusterFixture setup, to detect that we're setting up a multiversion cluster (similarly to ReplicaSetFixture), and instead of starting the node with --shardsvr, simply run the normal ReplicaSetFixture setup (which will effectively set the proper FCV), and then restart it as a shard.