As it were, QStringLists were not handled explicitly when comparing
QVariants. If both QStringLists contained only a single entry, they
were treated as QStrings - if both QStringLists were empty, there were
equal (correctly so) - but if one of the QStringLists had more than
one entry, the compare function fell through to returning always 1.
As discussed here: https://stackoverflow.com/a/38492467/3444217
Added rich comparison tests for all non-numerical, non-recursive
QVariants that support them (except QModelIndex and
QPersistentModelIndex)
Task-number: QTBUG-54893
Change-Id: Icc5480d9ba056ee5efe83da566c5829caa1509d7
Reviewed-by: Jędrzej Nowacki <jedrzej.nowacki@theqtcompany.com>