SOLR-6443: Disable test in 4x branch until the leaking cores can be resolved in trunk.

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1621338 13f79535-47bb-0310-9956-ffa450edef68
Revert smoke test update to java 8 for now

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1621339 13f79535-47bb-0310-9956-ffa450edef68