Delete chunks upon re-beginning a command buffer

* If a command buffer had an unbalanced begin/end, some chunks may still be left
  in the record that haven't been baked. Delete these before beginning to record
  again.

renderdoc/driver/vulkan/wrappers/vk_cmd_funcs.cpp

@@ -1320,6 +1320,8 @@ VkResult WrappedVulkan::vkBeginCommandBuffer(VkCommandBuffer commandBuffer,
              ToStr(record->bakedCommands->GetResourceID()).c_str());
     }
 
+    record->DeleteChunks();
+
     {
       CACHE_THREAD_SERIALISER();