repair: Speed up ranges calculation when small table optimization is on
Normally, during bootstrap, in repair_service::bootstrap_with_repair, we
need to calculate which range to sync data from carefully for the new
node. With small table optimization on, we pass a single full range and
all peer nodes to row level repair to sync data with. Now that we only
need to pass a single range and full peers, there is no need to calculate
the ranges and peers in repair_service::bootstrap_with_repair and drop
it later. The calculation takes time which slows down bootstrap, e.g.,
```
Jul 08 22:01:41.927785 cluster-scale-50-200-test-scayle-t-db-node-51209daa-93 scylla[5326]:
[shard 0:strm] repair - bootstrap_with_repair: started with
keyspace=system_distributed_everywhere, nr_ranges=23809
Jul 08 22:01:57.883797 cluster-scale-50-200-test-scayle-t-db-node-51209daa-93 scylla[5326]:
[shard 0:strm] repair - repair[79eac1a1-5d5b-4028-ae1c-06e68bec2d50]:
sync data for keyspace=system_distributed_everywhere, status=started,
reason=bootstrap, small_table_optimization=true
```
The range calculation took 15 seconds for system_distributed_everywhere
table.
To fix, the ranges calculation is skipped if small table optimization is
on for the keyspace.
Before:
cluster dev [ PASS ] cluster.test_boot_nodes.1 104.59s
After:
cluster dev [ PASS ] cluster.test_boot_nodes.1 89.23s
A 15% improvement to bootstrap 30 node cluster was observed.
Fixes#24817Closesscylladb/scylladb#24901
* github.com:scylladb/scylladb:
repair: Speed up ranges calculation when small table optimization is on
test: Add test_boot_nodes.py