L1 cache entries should not be passivated

L1 entries are stored in the same data container as the real entries. These can be evicted which is fine, however we don't want them to be passivated as this could be costly to write/read from the cache store. We should either prevent L1 cache entries from being passivated or have an option to allow for it.

Currently L1 entries are not differentiated from other entries except through the fact that they are mortal, which is used for other operations as well, which means they would need a placeholder of some kind to tell the container this is a L1 entry.