Akin to the successful tst_QStringApiSymmetry, add such a test for
generic containers, too. Yes, we have tst_collections, but it's a
cut'n'paste mess that makes it hard to systematically perform
cross-class checks for consistency. This new test, still in its
infancy, uses templates and thus ensures that exactly the same checks
are run on all containers.
Starting out with front()/back(), which the string classes were found
to lack, we will build this test up, as we did and continue to do with
the string API one.
Change-Id: I07323340b5612ecc658232b2776d788018010d0d
Reviewed-by: Lars Knoll <lars.knoll@qt.io>