compiler: emit type specific functions for aliases

If we have an alias for a struct or array that requires a
type-specific function, don't emit the function with the alias name.
Emit it with the struct/array as usual.

Test case is https://golang.org/cl/62531.

Change-Id: Ic194ea913a3a6fa42138706d0a6929b490733394
Reviewed-on: https://go-review.googlesource.com/62412
Reviewed-by: Than McIntosh <thanm@google.com>
1 file changed