vm_fault: improve interface for vm_fault_quick_hold_pages()

Provide (transitional) vm_fault_quick_hold_pages_e() function that
returns distinguishable errors in different failure situation. Also it
does not panic() on too short array case, but return an error, allowing
sometimes lessen the burden of the check from the caller.

vm_fault_quick_hold_pages() becomes a wrapper, that should be eliminated
eventually.

Reviewed by: imp, markj
Sponsored by: The FreeBSD Foundation
MFC after: 1 week
Differential revision: https://reviews.freebsd.org/D52165