- Make VulkanUnitTests depend on SPIRV-Tools.
- Build Vulkan DLLs but don't link statically with VulkanUnitTests.
- Don't use Unicode character set.
- Statically link runtime library.
- Fix narrowing conversion from 'VkCommandBufferUsageFlagBits' to
  'VkCommandBufferUsageFlags'.

Bug swiftshader:125

Change-Id: I7dbdc25c829cc76b5e05cd57cd9f85bf2d4e0903
Reviewed-on: https://swiftshader-review.googlesource.com/c/SwiftShader/+/26948Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Ben Clayton <bclayton@google.com>
Tested-by: Nicolas Capens <nicolascapens@google.com>