cmd/dist: apply final edits from CL 18199.

I broke the rule: never click the Submit button on the web.

Change-Id: If81a5cc31c1f28664960bad124cc596f5cab1222
Reviewed-on: https://go-review.googlesource.com/18203Reviewed-by: Russ Cox <rsc@golang.org>

src/cmd/dist/test.go

@@ -196,7 +196,7 @@ func (t *tester) run() {
 		}
 		dt := dt // dt used in background after this iteration
 		if err := dt.fn(&dt); err != nil {
-			t.runPending(dt) // in case that hasn't been done yet
+			t.runPending(&dt) // in case that hasn't been done yet
 			t.failed = true
 			if t.keepGoing {
 				log.Printf("Failed: %v", err)