Since #9259, CString in VulkanPlatform fall into the literal
constructor path. But we really want the null-terminated
(char const*) path. So we cast the strings to (char const*)
to enforce null-teriminated behavior.
RDIFF_BRANCH=pf/renderdiff-add-tolerance
We use Mesa's gallium swrast to render as the driver with
Filament's backend set to GL. We provide a few scripts to parse
the tests (as jsons) and run gltf_viewer to produce the rendering.