Update to include latest Test::Builder alpha

Also updated some tests that the new builder broke
Separate the extraction of hex values.

This way we can call it twice: first to count the size of output (and
sanity check the extraction indices), and the second time to actually
extract.  Otherwise with bad extraction code we will smash the stack.

Furthermore, this makes for cleaner code since the large #ifdef forest
(about differing long double formats, and different uv/nv/quad sizes)
is moved within the helper function.

Furthermore: IEEE 754 128-bit extraction was extracting wrong:
we need only the mantissa bits, and in the right nybble order.

Last but not least, handle the 'implicit bit' of IEEE 754 quadruple
and double-double (but which is explicitly *not* in the 80-bit format).
(If we handled the standard 64-bit format by explicit byte extraction,
instead of frexp+ldexp the hidden bit would be needed there, too.)
Add quadruple precision tests, verified by Craig Berry.

Also tentatively adding double-double tests, but those are probably bogus.

Also comment tweaks.
Little-endian double-double detection was wrong.
Comment tweaks.
Include longdblkind in perl -V output.
perldelta for b5b6210a9/#46947
Update blead to Test::Builder alpha 40

Fixes performance issues
Fixes a test failure specific to certain utf8 conditions
Fixes a broken win32+fork test

Committer's notes: 2nd Test-Simple patch applied;
corresponds to $Test::Simple::VERSION 1.301001_040
Fix finite/finitel/isfinite in configure.com.

VMS has had these for a very long time but we haven't been
admitting it.  Spotted by Jarkko.
When cross-compiling, copy cpan/Module-Metadata/

cpan/Module-Metadata/t/encoding.t needs some files in the
distribution to pass.
document what version \K was added in
spelling: till -> until
Revert Test::Builder changes in prep for 5.21.3

This reverts commit 6bdb88770f849c47b5c09e733ac460ce3e9dbc97
and commit 59c96aebdd56baf5d1979103046b1c6d4e308aa2, which
are causing the test suite to run much slower and which are
failing on some platforms.

http://nntp.perl.org/group/perl.perl5.porters/218678 has
further details, with RT 122538 being the ticket number.
perldelta typo fix: change a ',' to a '.'
perldelta for 3699825258c
perldelta for 4cedf205aa6e
perldelta for jhi double/float work
perldelta for 438f0014a812
perldelta for 438f0014a812, revised

It was actually 1.19 to 1.21, missed the earlier one.
perldelta for 54b7cb3

Delta for CPAN::Meta::Requirements version bump