SOLR-5652: test fixes: add 'plain' docvalue field variants to schema, and check codecs for support of missing docValues before trying to sort on them (merge r1562155)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1562160 13f79535-47bb-0310-9956-ffa450edef68