[Test] test cases for pred:iri-string

I created three test cases (all not very spectacular) for the predicate
pref:iri-string:

http://www.w3.org/2005/rules/wiki/IRI_from_RDF_Literal
http://www.w3.org/2005/rules/wiki/Multiple_IRIs_from_String
http://www.w3.org/2005/rules/wiki/Multiple_Strings_from_IRI

-- 
Jos de Bruijn            debruijn@inf.unibz.it
+390471016224         http://www.debruijn.net/
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No one who cannot rejoice in the discovery of
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