os: improve path check with direct index access

PR-URL: https://github.com/nodejs/node/pull/55434
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>
Reviewed-By: Juan José Arboleda <soyjuanarbol@gmail.com>

lib/os.js

@@ -26,7 +26,6 @@ const {
   Float64Array,
   NumberParseInt,
   ObjectDefineProperties,
-  StringPrototypeEndsWith,
   StringPrototypeSlice,
   SymbolToPrimitive,
 } = primordials;
@@ -184,9 +183,9 @@ function tmpdir() {
            process.env.TMP ||
            (process.env.SystemRoot || process.env.windir) + '\\temp';
 
-    if (path.length > 1 && StringPrototypeEndsWith(path, '\\') &&
-        !StringPrototypeEndsWith(path, ':\\'))
+    if (path.length > 1 && path[path.length - 1] === '\\' && path[path.length - 2] !== ':') {
       return StringPrototypeSlice(path, 0, -1);
+    }
 
     return path;
   }