generally protected by the VM page queue mutex. Instead of extending the
table lock to cover the PVO heads, add some asserts that the page queue
mutex is in fact held. This fixes several LORs and possible deadlocks.
This also adds an optimization to moea64_kextract() useful for
direct-mapped quantities, like UMA buffers. Being able to use this from
inside UMA removes an additional LOR.
cb8617b275