When importing a C++ class template instantiation, Swift translates the template parameter type names from C++ into their Swift equivalent.
For instance, `basic_string<wchar_t, char_traits<wchar_t>, allocator<wchar_t>>` gets imported as `basic_string<Scalar, char_traits<Scalar>, allocator<Scalar>>`: `wchar_t` is imported as `CWideChar`, which is a typealias for `Scalar` on most platforms including Darwin. Notice that Swift goes through the `CWideChar` typealias on the specific platform. Another instantiation `basic_string<uint32_t, char_traits<uint32_t>, allocator<uint32_t>>` also gets imported as `basic_string<Scalar, char_traits<Scalar>, allocator<Scalar>>`: `uint32_t` is also imported as `Scalar`. This is problematic because we have two distinct C++ types that have the same name in Swift.
This change makes sure Swift doesn't go through typealiases when emitting names of template parameters, so `wchar_t` would now get printed as `CWideChar`, `int` would get printed as `CInt`, etc.
This also encourages clients to use the correct type (`CInt`, `CWideChar`, etc) instead of relying on platform-specific typealiases.
rdar://115673622
