MB-25330: Pad up file to page boundary on windows
MB-25330: Pad up file to page boundary on windows

If there is an empty segment at the end of file
(possibly due to pure deletions during compaction), then
mmap() can fail on windows since we actually map more
space due to the AllocationGranularity requirements.

Change-Id: I6c4ce00a5e7d9af3cb905efbc422fec02a7d590d
Reviewed-on: http://review.couchbase.org/81205
Tested-by: Sundararaman Sridharan <333a3f71d3ad6e01fc953c4fa06bc1f3cd014910@couchbase.com>
Well-Formed: Build Bot <80754af91bfb6d1073585b046fe0a474ce868509@couchbase.com>
Reviewed-by: Steve Yen <ef850f73f7832052d3c6d9b5ddd3a1716d9a57f1@gmail.com>

couchbaselabs/moss,steveyen/moss,steveyen/moss