SOLR-6485: remove useless javadocs that are broken and violate precommit

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1631554 13f79535-47bb-0310-9956-ffa450edef68
SOLR-6540 Fix NPE from strdist() func when doc value source does not exist in a doc

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/trunk@1631555 13f79535-47bb-0310-9956-ffa450edef68