* We are really looking for persistent memory leaks here not fluctuations in
memory use. There are too many false positives from memory usage increasing up
high part-way through the iterations and then reducing down for the final
iteration, which could be many lazy or deferred things running and completing
over time.
* Even though a clear feels like it shouldn't dirty the image, it still means a
write to the image which we need to be sure to save as initial contents.
* This will let us run multiple windows (and multiple threads) relatively
easily.
* The hammer is fairly big, we move some things into the window that don't need
to be there necessarily if we have multiple windows on a single thread, but it
keeps things simple.
* This is better than testing by platform/platform version, because we can check
specifically for extensions and avoid running a test we know will fail because
extensions aren't supported.
* Instead of only doing a very lightweight check to see if the API is available
up-front, we now share the API initialisation among all API tests far enough
to determine availability of extensions, features, etc. Then we can precisely
determine which tests are available and which aren't before running.
* This is primarily useful for HLSL on Vulkan, but could be used with any other
combination. If multiple tools can perform the conversion, the highest
priority one is used.
* This is required because we add MAP_READ_BIT and the spec doesn't allow maps
that are both unsynchronized and reading.
* Also add a test for unsynchronised persistent maps, and update the
GL_Buffer_Updates test to not require a reference image but check each quad
individually for the expected colour.
* This is primarily for the benefit of GL/VK where we need to feature-detect for
some extensions or functionality that requires selecting a device, e.g. D3D12
can be more easily detected with a quick check.
* We'll run this once and cache the results when running tests from python so we
can do a better job of filtering out tests that the current machine doesn't
support.
baldurk