Feature test for a IE legacy bug

fix sniff introduced by @cpojer in
https://github.com/kentaromiura/mootools-core/commit/103f6489c697ca0a2ec
aa33c55c8929c92359e69 for fixing one of the lots of bugs of clone node
in explorer
ensuring it will work on strict environment
Merge pull request #2573 from kentaromiura/no-sniff-2-of-3-oldie-clonenode-bug

Feature test for a IE legacy bug