The alignment of VkWrapper is currently set to match the alignment of
uint64_t which isn't always correct. On some platforms (e.g. Linux x86)
the alignment of uint64_t inside and outside of a struct differ (8 vs
4). Using an alignment of 8 will cause swiftshader to miscalculate the
size of structs containing VkWrappers and the offset of different
fields into the struct. This is why the alignment of VkWrapper should
match that of uint64_t inside a struct, not outside of it.

Bug: chromium:967831
Change-Id: Ibf8240d13406413481cf87e9d45df4478c35be2f
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/32108
Kokoro-Presubmit: kokoro <noreply+kokoro@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Tested-by: Saman Sami <samans@chromium.org>