Xid recovery scans assume same list ordering

For RM driven recovery, two consecutive recovery scans are performed with a delay between. Only Xids appearing in both are eligible for recovery. This prevents momentarily prepared, normally executing branches from being incorrectly aborted.

RecoveryXids.toRecover incorrectly compares the content of the two lists, leading to some Xids not being recovered in a timely manner if the list content or order partially changes between scans.