Vulkan: Simplify descriptor set management - Descriptor logic is contained in ProgramExecutableVk and doesn't leak into ContextVk - Reduces CPU overhead by not having to constantly copy and resize the DescriptorSetDescBuilder - Simplifies decoupling of descriptor set of uniform buffers from that of other shader resources Bug: angleproject:426412564 Change-Id: Ic0926d0d466ea21f611c2b2c7b844e0bb9027c1b Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/6702410 Reviewed-by: Charlie Lao <cclao@google.com> Commit-Queue: mohan maiya <m.maiya@samsung.com> Reviewed-by: Shahbaz Youssefi <syoussefi@chromium.org>