Python: Port xmltodict tests

Author: RasmusWL

python/ql/test/experimental/library-tests/frameworks/XML/xmltodict.py

@@ -0,0 +1,6 @@
+import xmltodict
+
+x = "some xml"
+
+xmltodict.parse(x) # $ input=x
+xmltodict.parse(x, disable_entities=False) # $ input=x vuln='Billion Laughs' vuln='Quadratic Blowup'