Use more of the PageCacheRecycler stuff

This helps a bunch with memory but isn't perfect.

A few things we could really improve but I don't really feel like it now:
1.  Rebuild SliceWriter and SliceReader against Elasticsearch's IntArray
so that we can build a smaller and throw out XIntBlockPool.
2.  Cache the BytesRefHash between analyses - maybe use it instead of a
Set<String> for filtering and use the term that spits out the BytesRef
and the hashcode of the field at the same time.