Pull out the arbitrary factor of three as a named constant and
document its arbitrariness once.
Pull out the mask and bit used in each function's loop to the outer
layer of the loop, since they don't depend on the inner loop variable
(or the random value generated in that loop).
Use QTest::addRow() instead of constructing a string to pass to
newRow().
Change-Id: Ifacbcb390e00828fd47f51b0c73d0ad5f6bc8bdb
Reviewed-by: Mårten Nordheim <marten.nordheim@qt.io>
ce950bcbf7