This adds a broken test that demonstrates the issue seen in
https://github.com/select2/select2/issues/3990 where existing selected
options are being reset once Select2 is initialized. This issue cannot
be reproduced on the options page [1] because the issue only appear to
happen if the selected option is not the first one in the list of
possible options.
[1]: https://select2.github.io/examples.html#data-array
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