restore: Restore as many pages at once as possible
restore: Restore as many pages at once as possible

When the VMA being restored is not COW-ed we read pages from images
one-by-one which results in suboptimal pages.img access. Fix this
by reading as many pages from iamge at once as possible withing the
active pagemap and VMA.

Signed-off-by: Pavel Emelyanov <c9a32589e048e044184536f7ac71ef92fe82df3e@parallels.com>

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