mktables: Stop generating most leading zeros

mktables: Stop generating most leading zeros

Leading zeros were generated to conform with Unicode usage, but these
are machine-read files so this just takes up some extra space and extra
parsing cycles at run-time.  It's a small matter, but we should design
our files to be the most efficient possible.  It is possible to get more
human-readable files by using the -annotate option to mktables.

Certain files whose existence has been published have their formats
unchanged, in case some application is reading them.  The files contain
comments that their use is deprecated, but there is no warning generated
if they are opened and read, nor is it really feasible to add such a
warning.  At some time in the future, we may feel it's ok to remove
these files, as their contents have been available since v5.16 through a
stable API in Unicode::UCD, but until we remove them, we shouldn't
change their formats.

Not all other leading zeros are removed; just the ones that were
convenient to remove.