cmd/mbf: print extra stage3 information

This includes ident of all three stages and the matching checksum if check is passing.

Signed-off-by: Ophestra <cat@gensokyo.uk>

cmd/mbf/main.go

@@ -113,6 +113,7 @@ func main() {
 		"stage3",
 		"Check for toolchain 3-stage non-determinism",
 		func(args []string) (err error) {
+			_, _, _, stage1 := (rosa.Std - 2).NewLLVM()
 			_, _, _, stage2 := (rosa.Std - 1).NewLLVM()
 			_, _, _, stage3 := rosa.Std.NewLLVM()
 			var (
@@ -120,6 +121,11 @@ func main() {
 				checksum [2]unique.Handle[pkg.Checksum]
 			)
 
+			if pathname, _, err = cache.Cure(stage1); err != nil {
+				return err
+			}
+			log.Println("stage1:", pathname)
+
 			if pathname, checksum[0], err = cache.Cure(stage2); err != nil {
 				return err
 			}
@@ -134,6 +140,11 @@ func main() {
 					Got:  checksum[0].Value(),
 					Want: checksum[1].Value(),
 				}
+			} else {
+				log.Println(
+					"stage2 is identical to stage3",
+					"("+pkg.Encode(checksum[0].Value())+")",
+				)
 			}
 			return
 		},