Includes VK_EXT_provoking_vertex definitions in vulkan_core.h, allowing
to delete the custom vk_ext_provoking_vertex.h header.

The include of vulkan_fuchsia_extras.h into vulkan.h was manually added
back, and the definitions that are now part of vulkan_fuchsia.h were
removed from vulkan_fuchsia_extras.h.

https://github.com/KhronosGroup/Vulkan-Headers
revision 9af411e83fb08cd2bddc3ec771de89416a96cb91
tag v1.2.178

Bug: b/142379729
Change-Id: I83a248b792149a6019fa0a14afbf790297b0e6d0
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/54308Reviewed-by: Alexis Hétu <sugoi@google.com>
Kokoro-Result: kokoro <noreply+kokoro@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>