Upgrade Scalar-List-Utils from 1.46 to 1.47

Upgrade Scalar-List-Utils from 1.46 to 1.47

Note that the last few commits have reverted any local customisations to
1.46.  These were of two kinds. First, fixes for a tainting issue, the
last of which was just a cherry-pick from upstream, which should have made
it into 1.47 anyway.

The second were fixes to tests for netbsd-vax and Inf/Nan. I don't think
blead urgently needs these - we should wait for them to re-appear via the
normal upstream merging process. See
    https://rt.cpan.org/Public/Bug/Display.html?id=118470