Missing VirtualFile.run usage in DirectoryBrowserSupport (#8874)

* Missing `VirtualFile.run` usage in `DirectoryBrowserSupport`

* Might as well handle `containsSymLink` the same way. Will never matter for artifact display with either the built-in or pluggable managers, but could improve performance of workspace listing with slow agent connections.

* Checkstyle

---------

Co-authored-by: Daniel Beck <daniel-beck@users.noreply.github.com>

core/src/main/java/hudson/model/DirectoryBrowserSupport.java

@@ -325,9 +325,10 @@ private void serveFile(StaplerRequest req, StaplerResponse rsp, VirtualFile root
             } else
             if (serveDirIndex) {
                 // serve directory index
-                glob = baseFile.run(new BuildChildPaths(root, baseFile, req.getLocale()));
-                containsSymlink = baseFile.containsSymLinkChild(getOpenOptions());
-                containsTmpDir = baseFile.containsTmpDirChild(getOpenOptions());
+                var result = baseFile.run(new BuildChildPaths(baseFile, req.getLocale(), getOpenOptions()));
+                glob = result.glob;
+                containsSymlink = result.containsSymLink;
+                containsTmpDir = result.containsTmpDir;
             }
 
             if (glob != null) {
@@ -747,19 +748,32 @@ private int dirRank(VirtualFile f) {
         }
     }
 
-    private static final class BuildChildPaths extends MasterToSlaveCallable<List<List<Path>>, IOException> {
-        private VirtualFile root;
+    private static final class BuildChildPathsResult implements Serializable { // TODO Java 21+ record
+        private static final long serialVersionUID = 1;
+        private final List<List<Path>> glob;
+        private final boolean containsSymLink;
+        private final boolean containsTmpDir;
+
+        BuildChildPathsResult(List<List<Path>> glob, boolean containsSymLink, boolean containsTmpDir) {
+            this.glob = glob;
+            this.containsSymLink = containsSymLink;
+            this.containsTmpDir = containsTmpDir;
+        }
+    }
+
+    private static final class BuildChildPaths extends MasterToSlaveCallable<BuildChildPathsResult, IOException> {
         private final VirtualFile cur;
         private final Locale locale;
+        private final OpenOption[] openOptions;
 
-        BuildChildPaths(VirtualFile root, VirtualFile cur, Locale locale) {
-            this.root = root;
+        BuildChildPaths(VirtualFile cur, Locale locale, OpenOption[] openOptions) {
             this.cur = cur;
             this.locale = locale;
+            this.openOptions = openOptions;
         }
 
-        @Override public List<List<Path>> call() throws IOException {
-            return buildChildPaths(cur, locale);
+        @Override public BuildChildPathsResult call() throws IOException {
+            return new BuildChildPathsResult(buildChildPaths(cur, locale), cur.containsSymLinkChild(openOptions), cur.containsTmpDirChild(openOptions));
         }
     }
     /**