Investigate Clone performance

[rockfordlhotka]

Based on this thread (#4271) by @michaelcsikos, the Clone operation takes more than twice the time to do a data portal create/fetch operation.

This was confirmed by @rockfordlhotka in CSLA 9 by adding 10k child items to the PropertyPerf test app. The data portal create/fetch occurred in 2.8 seconds, the clone in 7.5 seconds.

The goal of this issue is to explore the way the clone occurs to see if there is any way to improve performance.