Update Gradle Testing Docs (#28970)
Update Gradle Testing Docs (#28970)

Attempting to run the REST tests, I noticed the testing instructions
  in the `TESTING.asciidoc` were outdated, so I fixed the paths.
  Steps I took to test:

  * Ran `./gradlew :distribution:packages:rpm:assemble` and make sure
  RPM is created in `./distribution/packages/rpm/build/distributions/`

  * Ran testing commands and verified the REST tests ran.
strapdata/elassandra,vroyer/elassandra,vroyer/elassandra,vroyer/elassandra,strapdata/elassandra,strapdata/elassandra,strapdata/elassandra,strapdata/elassandra