This time exercising series of buffer updates and texture uploads
within proper, on-screen frames. (particularly interesting for dynamic
buffers in case the double (or more) buffering and having multiple
frames in flight involves special bookkeeping for these - using
'offscreen' frames like in other test cases does not necessarily
exercise all of this)
Change-Id: Id470919d27037359a1f0346a50a2a0e3966f5cd2
Reviewed-by: Andy Nichols <andy.nichols@qt.io>
5a496a614b