disk_folders: bound the walk at 25 s, below the tool runner's 30 s, and say findings as lines (issue 1804)

modules/disk-load/cmd/disk-load/folders.go

@@ -13,7 +13,7 @@ import (
 )
 
 // FolderBudget is how long a folder walk may take before it answers what it has measured.
-const FolderBudget = 60 * time.Second
+const FolderBudget = 25 * time.Second
 
 // namedUnreadable is how many unreadable folders are named; the rest are only counted.
 const namedUnreadable = 50
@@ -130,7 +130,7 @@ func (m *Machine) Folders(path string, depth, limit int) (FolderReport, error) {
 	if len(r.Skipped) > 0 {
 		said = append(said, "other filesystems not entered: "+strings.Join(r.Skipped, ", "))
 	}
-	r.Said = strings.Join(said, "; ")
+	r.Said = said
 	return r, nil
 }