FacetFieldProcessorByHashDV is reconstructing FieldInfos on every instantiation

The FacetFieldProcessorByHashDV constructor is currently calling:

FieldInfo fieldInfo = fcontext.searcher.getSlowAtomicReader().getFieldInfos().fieldInfo(sf.getName());

Which is reconstructing FieldInfos each time. Simply switching it to:

FieldInfo fieldInfo = fcontext.searcher.getFieldInfos().fieldInfo(sf.getName());

 
causes it to use the cached version of FieldInfos in the SolrIndexSearcher.

On my index the FacetFieldProcessorByHashDV is 2-3 times slower than the legacy facets without this fix.