Change sort order of shard stats in CCR test

This commit changes the sort order of shard stats that are collected in
CCR retention lease integration tests. This change is done so that
primaries appear first in sort order.

Author: jasontedor

x-pack/plugin/ccr/src/test/java/org/elasticsearch/xpack/ccr/CcrRetentionLeaseIT.java

@@ -568,7 +568,7 @@ private List<ShardStats> getShardsStats(final IndicesStatsResponse stats) {
         return Arrays.stream(stats.getShards())
                 .sorted((s, t) -> {
                     if (s.getShardRouting().shardId().id() == t.getShardRouting().shardId().id()) {
-                        return Boolean.compare(s.getShardRouting().primary(), t.getShardRouting().primary());
+                        return -Boolean.compare(s.getShardRouting().primary(), t.getShardRouting().primary());
                     } else {
                         return Integer.compare(s.getShardRouting().shardId().id(), t.getShardRouting().shardId().id());
                     }