vfs: remove unused utility functions from module_hooks

Remove getActiveVFSCount() and areHooksInstalled() functions that
were exported but never used anywhere in the codebase.

This improves code coverage by removing unreachable code.

Author: mcollina

lib/internal/vfs/module_hooks.js

@@ -676,27 +676,9 @@ function installHooks() {
   hooksInstalled = true;
 }
 
-/**
- * Get the count of active VFS instances.
- * @returns {number}
- */
-function getActiveVFSCount() {
-  return activeVFSList.length;
-}
-
-/**
- * Check if hooks are installed.
- * @returns {boolean}
- */
-function areHooksInstalled() {
-  return hooksInstalled;
-}
-
 module.exports = {
   registerVFS,
   unregisterVFS,
   findVFSForStat,
   findVFSForRead,
-  getActiveVFSCount,
-  areHooksInstalled,
 };