Some changes to improve test robustness.
 - Reduce total number of iterations in 'loadgen' stored
    procedure
   - Reduces binlog volume, cpu load
 - Introduce sleep (0.1) in 'loadgen' stored procedure
   - Increases probability of multiple discrete
     epochs appearing in Binlog
 - Improve sensitivity of error log analysis, previously
   required > 1 entry, now require >= 1 entry.

Testcase runtime is reduced as a result.
Hopefully the overall effect is to reduce spurious failures.

Approved by : Priyanka Sangam <priyanka.sangam@oracle.com>