Using https://github.com/KhronosGroup/Vulkan-Headers at tag v1.2.141.

Vulkan-Hpp is useful for writing unit tests and microbenchmarks, since
it includes support for loading a specific dynamically linked library:
https://github.com/KhronosGroup/Vulkan-Hpp#extensions--per-device-function-pointers

It also provides some abstraction to make tests more succinct and less
bug prone.

Bug: b/144696871
Change-Id: I4b22aefd205c01094e525b051b088ea9df14cca8
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/45568
Presubmit-Ready: Nicolas Capens <nicolascapens@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Antonio Maiorano <amaiorano@google.com>