deprecate or remove B-Debug

[rurban]

See https://rt.cpan.org/Public/Bug/Display.html?id=122599
The suggestion was use if "$]" >= 5.027003, 'deprecate';, which should be use if $] >= 5.027003 and only for the core version of course.
They want to keep it for one more major release and remove it with 5.30.

This sounds bad, but I haven't made up my mind yet for a such a trivial module nobody needs.

If, the if module dependency is a stopper.

BEGIN { if ($] >= 5.027003) { require deprecate; import deprecate; } }

would be the right thing to do.

class needs also to be replaced with B::class, and $cv->GV needs to be avoided for CvNAMED

[rurban]

decision: deprecate with 5.27.3, 5.27.1c. remove with 5.30.

[rurban]

deprecated with 1.25, 189e644