UCD.t: Skip PropValueAliases tests on early Unicodes
UCD.t: Don't use BEL for $/

This causes failures on early Unicode releases, and is not necessary
Unicode::UCD::casefold(): Don't use .txt file for source

This converts this function to using the outputs of prop_invmap() to get
its casefolding definitions.  This allows it to work on versions of
Unicode which don't have this file, allows the file to not have to be
installed, and removes this function from having to be different on
EBCDIC platforms (which wasn't coded anyway).
installperl: CaseFolding.txt no longer needed

A previous commit has removed the dependency on this file.
charnames.t: Skip testing named sequences if don't exist

Instead of dying when applied to a Unicode version that doesn't have
named sequences, skip them.
charnames.t: Indent newly formed block
charnames.t: Skip hangul syllable testing for early Unicodes

If the Unicode release doesn't contain hangul syllables, just skip those
tests
charnames.t: Fix to work on Unicodes without NameAliases

This is a recent addition.  Use alternate means if the file doesn't
exist in the Unicode release, or is for a non-ASCII platform (as the
alternate means should take care of the translation in that case).
charnames.t: White-space only

Indent newly formed block
mktables: Extend Name_Alias property to early Unicode releases

This uses this property so that charnames can work on early Unicode
releases, by including all the aliases that were previously defined in
charnames until Unicode 6.1 started defining them itself.
fold_grind.t: read environment variable just once

Setting a lexical variable to the environment variable made it easier
for me to temporarily override things during a sequence of tests that
took place on many different occasions where I needed this set and kept
forgetting to set the environment variable.
fold_grind.t: Allow to work on early Unicodes

If the version of Unicode being tested doesn't have the modern
casefolding .txt file, get the values from Unicode::UCD.  Also for
EBCDIC, where otherwise the file would have to be translated.
mk_PL_charclass.pl: Allow to work on early Unicodes

If the version of Unicode being compiled doesn't have the modern
casefolding .txt file, get the values from Unicode::UCD.  Also for
EBCDIC, where otherwise the file would have to be translated.
reg_fold.t: Allow to work on early Unicodes

If the version of Unicode being compiled doesn't have the modern
casefolding .txt file, get the values from Unicode::UCD.  Also for
EBCDIC, where otherwise the file would have to be translated.
reg_fold.t: Fix test to work on EBCDIC platform

I noticed these constants won't work on EBCDIC.
Unicode::UCD: Allow some fncs to work under minitest

Some of the functions defined in this module are needed for minitest,
where dclone is not available.  This defines and uses a substitute
dclone when Storable::dclone is not available.

It also conditionally loads Unicode::Normalize.  The function that uses
that module is not executed in minitest.
t/uni/case.pl: Use warnings and strict
t/uni/case.pl: Allow to work on early Unicodes

This changes case.pl to use Unicode::UCD instead of directly reading
the casing files.  This allows it to be used on Unicode releases that
don't have those files, as Unicode::UCD has the intelligence to cope
with that.  The EBCDIC code in it can be removed as Unicode::UCD should
cope with that as well.

As a result, the .t's that call it have a slightly different API.
Add all_casefolds()

This function returns the entire structure that casefold() builds.  It
is useful for a .t.
uni/fold.t: Use Unicode::UCD::casefolds() for inputs

This allows this .t to work on early Unicodes.