Vulkan: Sampler structs in arrays. Samplers are extracted from arrays of struct uniforms similarly as with non-arrays. They are named according to the variable name, array element and sampler field name. Nested structs to come later. Bug: angleproject:2494 Change-Id: Ie2f5f7bd1f747e73b3c6b505b2b1043cfe1073b5 Reviewed-on: https://chromium-review.googlesource.com/1101568 Commit-Queue: Jamie Madill <jmadill@chromium.org> Reviewed-by: Olli Etuaho <oetuaho@nvidia.com>