RDS: add reconnect retry scheme for stalled connections

RDS: add reconnect retry scheme for stalled connections

RDS IB connections gets stalled at times and letting the connections
take its sweet time to reconnect. On passive side, we wait for 15 seconds
for such stalled connections which is too slow based on application
IO timeouts. IB connections are established in milliseconds so we better
drop these stuck connections early and retry.

The retry timeout is kept tunable via reconnect_retry_ms sysctl. The
upper bound for retries is tunbale via rds_sysctl_reconnect_max_retries.

Orabug: 22347191

Tested-by: Michael Nowak <michael.nowak@oracle.com>
Tested-by: Rafael Alejandro Peralez <rafael.peralez@oracle.com>
Tested-by: Liwen Huang <liwen.huang@oracle.com>
Tested-by: Hong Liu <hong.x.liu@oracle.com>
Reviewed-by: Mukesh Kacker <mukesh.kacker@oracle.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>