We only need the cursor type to know if the cursor references a deleted
cell, don't unpack the cell, just grab the type.
Remove unnecessary cell unpack call, somebody cut-and-pasted too quickly.
We only need the cursor type to know if the WT_ITEY is an overflow key,
don't unpack the cell, just grab the type.
We only need the cell type to know if the cell references a leaf page
with no overflow items, don't unpack the cell, just grab the type.
Don't call realloc() every time we need to extend the col-var repeats
array: the first time we discover we need the repeats array, walk the
entire page and figure out how big it needs to be.  (Two-passes over
the page must be better than N calls to realloc...)