Hallvard Furuseth authored Jul 25, 2017 and Howard Chu committed Oct 10, 2020

P_ADM_FLAGS flags are tied to the page, even through page_loose-alloc.
OTOH mdb_page_split() should only duplicate the relevant flags.

This is just the code for the feature, P_ADM_FLAGS is 0 for now.
We'll need it for P_HIDESPILL later.