cmd/gopherbot: copy Testing label, wait longer for CherryPickApproved

Testing is another label we actively use during backport review to
indicate that a backport involves a fix to test code only. Copy it
by default too.

Since cherry-pick issues to fix or skip broken or flaky tests may get
approved well before their fix is developed, give such issues more time
before auto-closing them as obsolete.

Change-Id: Ia0645b08cd431e521d15ee97de19d12572c30dd1
Reviewed-on: https://go-review.googlesource.com/c/build/+/519376
Reviewed-by: Carlos Amedee <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Auto-Submit: Dmitri Shuralyov <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Run-TryBot: Dmitri Shuralyov <[email protected]>

Author: dmitshur

cmd/gopherbot/gopherbot.go

@@ -1253,9 +1253,9 @@ func (b *gopherbot) closeStaleWaitingForInfo(ctx context.Context) error {
 			}
 
 			deadline := waitStart.AddDate(0, 1, 0) // 1 month
-			if gi.HasLabel("CherryPickCandidate") {
-				// Cherry-pick candidates may sometimes need to wait for fixes
-				// to soak on the order of months, so give them more time.
+			if gi.HasLabel("CherryPickCandidate") || gi.HasLabel("CherryPickApproved") {
+				// Cherry-pick issues may sometimes need to wait while
+				// fixes get prepared and soak, so give them more time.
 				deadline = waitStart.AddDate(0, 6, 0)
 			}
 			if now.Before(deadline) {
@@ -1728,6 +1728,7 @@ func (b *gopherbot) openCherryPickIssues(ctx context.Context) error {
 		for _, l := range [...]string{
 			"Security",
 			"GoCommand",
+			"Testing",
 		} {
 			if gi.HasLabel(l) {
 				extraLabels = append(extraLabels, l)