When creating a strongly consistent table, wait for the table's raft
servers to start and be ready to serve queries before completing the
operation. We want the create table operation to absorb the delay of
starting the raft groups instead of the first queries.
The create table coordinator commits and applies the schema statement,
then it waits for all hosts that have a tablet replica to create and
start the raft groups for the table's tablets. It does this by sending
an RPC to all the relevant hosts that executes a group0 barrier, in
order to ensure the table and raft groups are created, then waits for
all raft groups on the host to finish starting and be ready.
Fixes SCYLLADB-807
5a5c7c6241