Vulkan CTS 1.1.6.1 New tests: * Tests for VK_KHR_separate_depth_stencil_layouts Fixes: * Add missing write to PointSize * Add timelineSempahore to mandatory ext features * Fix check in testMandatoryExtensions * Remove deprecated std::bind2nd() call * Add scissor matching renderArea to descriptor indexing tests * Check available functionality with context method * Fix incorrect assumption for pipeline cache hit * Fixes VS num instances assumption