This is just a refactoring, where the 'emulated' types still map to
the same types as before. They are represented using small integer
values reinterpret-casted as sw::Type*, while non-emulated types
correspond directly to llvm::Type pointers.

Bug swiftshader:78

Change-Id: I88c0b932a45119ce500821068d8fb5faa2ccbb92
Reviewed-on: https://swiftshader-review.googlesource.com/11048Tested-by: Nicolas Capens <nicolascapens@google.com>
Reviewed-by: Alexis Hétu <sugoi@google.com>
Reviewed-by: Nicolas Capens <nicolascapens@google.com>