[dev.link] cmd/link: sort DynidSyms

Sort DynidSyms to ensure a deterministic build.

Fix Solaris build.

Change-Id: I6c01cb3dec5e46b3d881e720e3c2079643b5c7c7
Reviewed-on: https://go-review.googlesource.com/c/go/+/230277
Run-TryBot: Cherry Zhang <cherryyz@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Than McIntosh <thanm@google.com>
Reviewed-by: Jeremy Faller <jeremy@golang.org>

src/cmd/link/internal/loader/loader.go

@@ -1276,6 +1276,7 @@ func (l *Loader) DynidSyms() []Sym {
 	for s := range l.dynid {
 		sl = append(sl, s)
 	}
+	sort.Slice(sl, func(i, j int) bool { return sl[i] < sl[j] })
 	return sl
 }