lib: remove sources of permanent deopts

PR-URL: nodejs#10789
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Matteo Collina <matteo.collina@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>

lib/fs.js

@@ -1572,7 +1572,7 @@ fs.realpathSync = function realpathSync(p, options) {
     }
 
     var resolvedLink;
-    const maybeCachedResolved = cache && cache.get(base);
+    var maybeCachedResolved = cache && cache.get(base);
     if (maybeCachedResolved) {
       resolvedLink = maybeCachedResolved;
     } else {
@@ -1585,8 +1585,8 @@ fs.realpathSync = function realpathSync(p, options) {
 
       // read the link if it wasn't read before
       // dev/ino always return 0 on windows, so skip the check.
-      let linkTarget = null;
-      let id;
+      var linkTarget = null;
+      var id;
       if (!isWindows) {
         id = `${stat.dev.toString(32)}:${stat.ino.toString(32)}`;
         if (seenLinks.hasOwnProperty(id)) {

lib/module.js

@@ -179,8 +179,8 @@ Module._findPath = function(request, paths, isMain) {
   }
 
   var exts;
-  const trailingSlash = request.length > 0 &&
-                        request.charCodeAt(request.length - 1) === 47/*/*/;
+  var trailingSlash = request.length > 0 &&
+                      request.charCodeAt(request.length - 1) === 47/*/*/;
 
   // For each path
   for (var i = 0; i < paths.length; i++) {
@@ -190,7 +190,7 @@ Module._findPath = function(request, paths, isMain) {
     var basePath = path.resolve(curPath, request);
     var filename;
 
-    const rc = stat(basePath);
+    var rc = stat(basePath);
     if (!trailingSlash) {
       if (rc === 0) {  // File.
         if (preserveSymlinks && !isMain) {