CL 157557 changes the compiler to add one byte padding to
    non-empty struct ending with a zero-sized field. Add the same
    padding to the FFI type, so reflect.Call works.
    
    This fixes test/fixedbugs/issue26335.go in the main repo.
    
    Reviewed-on: https://go-review.googlesource.com/c/158018

From-SVN: r267956