showplan messages for simulated statistics

When set statistics simulate is enabled and there are simulated statistics available, showplan prints the following message:

Optimized using simulated statistics.

If the server on which the simulation tests are performed has the parallel query options set to smaller values than the simulated values, showplan output first displays the plan using the simulated statistics, and then an adjusted query plan. If set noexec is turned on, the adjusted plan is not displayed.