[SPARK-21584][SQL][SPARKR] Update R method for summary to call new implementation

## 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.