Summary
__verbose_dump_cache_single prints out the size of each page in cache, but when it does so it computes size as bytes / WT_MEGABYTE, and for small byte sizes under 1MB integer division truncates this to zero. There are other uses of x / WT_MEGABYTE that may behave similarly.

Motivation
Priority is P5 as we only see this when enabling debug traces and also dumping info about pages smaller than 1 MB. If encountered devs can easily change WT_MEGABYTE to WT_KILOBYTE as a temporary fix to continue with their task.

Acceptance Criteria (Definition of Done)
Performing a cache dump with small sized pages yields results like
leaf: 1 pages, 228KB, 0/1 clean/dirty pages, 0/228/146 clean/dirty/updates KB, 228KB max page, 228KB max dirty page
or
leaf: 1 pages, 0.228MB, 0/1 clean/dirty pages, 0/0.228/0.146 clean/dirty/updates MB, 0.228MB max page, 0.228MB max dirty page
rather than
leaf: 1 pages, 0MB, 0/1 clean/dirty pages, 0/0/0 clean/dirty/updates MB, 0MB max page, 0MB max dirty page