Use two template parameters for the haystack and needle types, to test
all possible combinations of all argument types.
Note that the tests for QByteArray::count() are removed: it doesn't
make sense to have them in tst_qstringapisymmetry, and we already have
the symmetry tests for QByteArray in tst_qbytearrayapisymmetry.
Change-Id: I33901fd135eb7433f0d45300a7248aef4d40324a
Reviewed-by: Marc Mutz <marc.mutz@qt.io>
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
Reviewed-by: Edward Welbourne <edward.welbourne@qt.io>
ebfe4318b8