When updating tuples, resize tuple segment to maximum length if possible

[GoogleCodeExporter]

At present during updates existing tuple segments are not resized even if
there is space available on the pages. This causes following inefficiency:
if a tuple grows beyond its original size, instead of resizing the tuple
segment, an additional tuple segment will be allocated (possibly on the
same page) and linked to the previous segment.

Original issue reported on code.google.com by [email protected] on 16 Aug 2008 at 12:14