Try a forge clone again when its name lookup fails (issue 1773)

A build or check failed now and then on 'Could not resolve host:
novox.internal' between clones that resolved the same name, and its
whole delivery failed with it. A clone whose lookup failed reached
nothing, so it is cloned again with a growing pause for up to 60 s,
each retry said in the build's log as the resolver not answering;
past the bound it fails saying so. Any other git failure fails at
once, as before. Covers a module's own clone, an artifact's context
and a check's repositories.

internal/builder/check.go

@@ -428,7 +428,8 @@ func Check(ctx context.Context, run Runner, spec CheckSpec, workspace, registry
 	// clone clones a repository and checks out ref; readAt keeps which, by directory.
 	readAt := map[string]string{}
 	clone := func(repository, ref, dir string) error {
-		if _, err := run(ctx, root, "git", cloneWith(credentials, "clone", "--quiet", repository, dir)...); err != nil {
+		if err := cloneFromForge(ctx, run, root, redact.redact(repository), filepath.Join(root, dir),
+			cloneWith(credentials, "clone", "--quiet", repository, dir), say); err != nil {
 			return fmt.Errorf("cannot clone %s: %s", redact.redact(repository), redact.redact(err.Error()))
 		}
 		if err := recordedWithoutUserinfo(ctx, run, filepath.Join(root, dir), repository); err != nil {