[NTOSKRNL] Misc fixes to VACB reference counting

[NTOSKRNL] Misc fixes to VACB reference counting
This fixes various bugs linked to VACB counting:
- VACB not released when it should be
- Reference count expectations not being accurate

For the record, VACB should always have at least a reference
count of 1, unless you are to free it and removed it from
any linked list.

This commit also adds a bunch of asserts that should
help triggering invalid reference counting.

It should also fix numerous ASSERT currently triggered and
may help fixing random behaviours in Cc.

CORE-14285
CORE-14401
CORE-14293