testing for invalid idn combinations

[ctr49]

On periodic dnstwist invocations of the homoglyph fuzzer I see almost daily flaps on many info domain variations.
I'm not sure if the returned ServFails (that come and go) are related to the invalid IDN combination, but diving into the details I found that dnstwist seems to create homoglpyh variations of the original domain that couldn't be registered with Afilias according to their (language/alphabet specific) IDN tables.

E.g. as far as I can tell the combination of the letters í (U+00ED) and ƈ (U+0188) cannot be both found in any supported alphabet for .info

I'm not sure if this intentional or not but wanted to leave it here if others run into a similar issue.