call to ReplSetTest.restart in shard_identity_rollback.js is racy

The call to restart() waits to connect to the restarted node by default, but in this case the node is expected to crash after starting up, so the call to restart is racy and can fail if the node crashes before restart() is able to connect to it.

The test should pass {waitForConnect: false} as the options object to this call to restart.