bug 15022: Need a way to specify dummy descriptors for unused bindings (WIP)

Add binding to VkDescriptorSetLayoutBinding.

https://cvs.khronos.org/bugzilla/show_bug.cgi?id=15022
diff --git a/tests/vkrenderframework.cpp b/tests/vkrenderframework.cpp
index 2fa1e61..1d003c9 100644
--- a/tests/vkrenderframework.cpp
+++ b/tests/vkrenderframework.cpp
@@ -501,6 +501,7 @@
     vector<VkDescriptorSetLayoutBinding> bindings;
     bindings.resize(m_type_counts.size());
     for (int i = 0; i < m_type_counts.size(); i++) {
+        bindings[i].binding = i;
         bindings[i].descriptorType = m_type_counts[i].type;
         bindings[i].arraySize = m_type_counts[i].descriptorCount;
         bindings[i].stageFlags = VK_SHADER_STAGE_ALL;