The end of a cpimport adds a delay which is 1 second multiplied by the
number of PMs. This in-turn is multipled up with the number of
connections/threads causing a long delay when you have several PMs.
The delay is not required as we already have a 20ms delay and we will
re-enter the recv() if there is no data and we are still connected.
This does the following:
* Switch resource manager to a singleton which reduces the amount of
times the XML data is scanned and objects allocated.
* Make the I_S tables use the FE implementation of the system catalog
* Make the I_S.columnstore_columns table use the RID list cache
* Make the extentmap pre-allocate a vector instead of many small allocs
