I think we want to stop doing this for 5.
It should be really cheap to enumerate and get stats for all of the SolrInfoMBeans, but between this and
SOLR-6747, you will overall call getStatistics far too much.
They are added twice because all request handlers are added using their path as the key, and then whatever the SolrResourceLoader has created is added using the default getName (the full class name) as the key.
I think we should start only allowing an object to appear once in the bean map in 5.0. The way the code currently works, the replication handler objects would take precedence, which seems right to me.