## What changes were proposed in this pull request?
SPARK-21100 introduced a new `summary` method to the Scala/Java Dataset API that included expanded statistics (vs `describe`) and control over which statistics to compute. Currently in the R API `summary` acts as an alias for `describe`. This patch updates the R API to call the new `summary` method in the JVM that includes additional statistics and ability to select which to compute.
This does not break the current interface as the present `summary` method does not take additional arguments like `describe` and the output was never meant to be used programmatically.
## How was this patch tested?
Modified and additional unit tests.
Author: Andrew Ray <ray.andrew@gmail.com>
Closes#18786 from aray/summary-r.
5c9b301727