* Identify members that are owning handles with a comment
* Reorder these members in creation order
* Reorder explicit destruction of these members in reverse order in destructors
* Replace raw pointers with unique_ptrs, but call reset explicitly in destructors to maintain reverse destruction order
* Define VULKAN_HPP_NO_NODISCARD_WARNINGS to future-proof for C++17 and up
* Remove vestigial vk::UniqueShaderModule and vk::UniquePipeline usage

Bug: b/176981107
Change-Id: Ia090be98c2f8ed47701dfc92388547985e5c57b4
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/51829Tested-by: Antonio Maiorano <amaiorano@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Commit-Queue: Antonio Maiorano <amaiorano@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>