Increase CTS checkout timeout when rolling CTS

The default behaviour is a 1 minute timeout, which depending on
network load and other factors, may not be enough time to clone the
CTS repo when running the tool.

Increasing the timeout for this step to 10 minutes, since the tool is
expected to take a significant amount of time to run, so a bit of
extra time on setup isn't noticable.

Change-Id: If51ed154a8b2373bb9b246f29467fb17c7d7e345
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/119300
Kokoro: Kokoro <noreply+kokoro@google.com>
Commit-Queue: Dan Sinclair <dsinclair@chromium.org>
Reviewed-by: Dan Sinclair <dsinclair@chromium.org>
Auto-Submit: Ryan Harrison <rharrison@chromium.org>

tools/src/cmd/cts/roll/roll.go

@@ -589,7 +589,7 @@ func (r *roller) findExistingRolls() ([]gerrit.ChangeInfo, error) {
 // checkout performs a git checkout of the repo at host to dir at the given hash
 func (r *roller) checkout(project, dir, host, hash string) (*git.Repository, error) {
 	log.Printf("cloning %v to '%v'...", project, dir)
-	repo, err := r.git.Clone(dir, host, nil)
+	repo, err := r.git.Clone(dir, host, &git.CloneOptions{Timeout: time.Minute * 10})
 	if err != nil {
 		return nil, fmt.Errorf("failed to clone %v: %v", project, err)
 	}