SOLR-4952: make TestConfig use solrconfig.snippet.randomindexconfig.xml - this involved moving some 'default' tests arround, prunning down solrconfig-termindex.xml, and renaming solrconfig-termindex.xml -> solrconfig-test-misc.xml since the name 'termindex' no longer makes sense (merge r1513312)

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1513325 13f79535-47bb-0310-9956-ffa450edef68