fixup! fs: add a fast-path for readFileSync utf-8

Backport-PR-URL: nodejs#48658

Author: anonrig

lib/fs.js

@@ -471,8 +471,8 @@ function readFileSync(path, options) {
 
   const isUserFd = isFd(path); // File descriptor ownership
 
-  // TODO: Do not handle file descriptor ownership for now.
-  if (!isUserFd && options.encoding === 'utf8') {
+  // TODO(@anonrig): Do not handle file descriptor ownership for now.
+  if (!isUserFd && (options.encoding === 'utf8' || options.encoding === 'utf-8')) {
     return readFileSyncUtf8(getValidatedPath(path), stringToFlags(options.flag));
   }