SOLR-6223: SearchComponents may throw NPE when using shards.tolerant and there is a failure in the 'GET_FIELDS/GET_HIGHLIGHTS/GET_DEBUG' phase

git-svn-id: https://svn.apache.org/repos/asf/lucene/dev/branches/branch_4x@1607899 13f79535-47bb-0310-9956-ffa450edef68