## What changes were proposed in this pull request?

Sbt compile and test should also run scalastyle. This makes it less likely you forget to run scalastyle and fail in jenkins. Scalastyle results are cached for efficiency.

This patch was originally written by ahirreddy; I just fixed it up to work with scalastyle 0.8.0.

## How was this patch tested?

Tested manually with `build/sbt package`.

Author: Eric Liang <ekl@databricks.com>

Closes #12555 from ericl/scalastyle.