This enables a truncating resize() to be implemented. It is similar to
destroyAll(), but updates the size() as it goes, so it is safe to use
outside a container's destructor (and doesn't necessarily destroy all
elements).
The appendInitialize test was repurposed and now doubles as an
additional test for QArrayDataOps as well as exercising SimpleVector's
resize().
Change-Id: Iee94a685c9ea436c6af5b1b77486734a38c49ca1
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>