repair: Fix rx_hashes_nr metrics (#5213)
repair: Fix rx_hashes_nr metrics (#5213)

In get_full_row_hashes_with_rpc_stream and
repair_get_row_diff_with_rpc_stream_process_op which were introduced in
the "Repair switch to rpc stream" series, rx_hashes_nr metrics are not
updated correctly.

In the test we have 3 nodes and run repair on node3, we makes sure the
following metrics are correct.

assertEqual(node1_metrics['scylla_repair_tx_hashes_nr'] + node2_metrics['scylla_repair_tx_hashes_nr'],
   	    node3_metrics['scylla_repair_rx_hashes_nr'])
assertEqual(node1_metrics['scylla_repair_rx_hashes_nr'] + node2_metrics['scylla_repair_rx_hashes_nr'],
   	    node3_metrics['scylla_repair_tx_hashes_nr'])
assertEqual(node1_metrics['scylla_repair_tx_row_nr'] + node2_metrics['scylla_repair_tx_row_nr'],
   	    node3_metrics['scylla_repair_rx_row_nr'])
assertEqual(node1_metrics['scylla_repair_rx_row_nr'] + node2_metrics['scylla_repair_rx_row_nr'],
   	    node3_metrics['scylla_repair_tx_row_nr'])
assertEqual(node1_metrics['scylla_repair_tx_row_bytes'] + node2_metrics['scylla_repair_tx_row_bytes'],
   	    node3_metrics['scylla_repair_rx_row_bytes'])
assertEqual(node1_metrics['scylla_repair_rx_row_bytes'] + node2_metrics['scylla_repair_rx_row_bytes'],
            node3_metrics['scylla_repair_tx_row_bytes'])

Tests: repair_additional_test.py:RepairAdditionalTest.repair_almost_synced_3nodes_test
Fixes: #5339
Backports: 3.2
scylladb/scylla,avikivity/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla