Subzero does not know the element types of vectors, so pass it as an
argument. Also deprecate createSwizzle() and createMask() from
Nucleus since we only need Float4 Swizzle().

Bug swiftshader:15

Change-Id: I38b630f48f8f43e1248338d564a7406d7c8cd5ef
Reviewed-on: https://swiftshader-review.googlesource.com/7395Tested-by: Nicolas Capens <capn@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <capn@google.com>