Previously we were using raw zero-based integer values
for roles in QtAbstractItemModel tests.
Roles starting from 0x0 to 0xFF are reserved for pre-defined roles
defined in Qt::ItemDataRole enum.
This change will change the base role value to Qt::UserRole.
It will later help us to use QAbstractItemModelTester as this
tester class expects certain types from pre-defined role values.
Task-number: QTBUG-132880
Change-Id: Ie19739cd7bf49829fe58f5ad53078942d47a433b
Reviewed-by: Assam Boudjelthia <assam.boudjelthia@qt.io>
967d9b8cf2