SOLR-4952: get all manged schema tests using solrconfig.snippet.randomindexconfig.xml - mainly by removing several solrconfig-*-managed-schema.xml files and using sys props in solrconfig-managed-schema.xml (merge r1513611)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1513616 13f79535-47bb-0310-9956-ffa450edef68