fixup! path: fix posix.relative() on Windows

Author: Trott

lib/path.js

@@ -25,10 +25,13 @@ const {
   FunctionPrototypeBind,
   RegExp,
   StringPrototypeCharCodeAt,
+  StringPrototypeIndexOf,
   StringPrototypeLastIndexOf,
+  StringPrototypeReplace,
   StringPrototypeSlice,
   StringPrototypeToLowerCase,
 } = primordials;
+
 const {
   CHAR_UPPERCASE_A,
   CHAR_LOWERCASE_A,
@@ -1018,9 +1021,12 @@ const posix = {
       const path = i >= 0 ?
         args[i] :
         (() => {
-          const _ = process.cwd()
-            .replace(new RegExp(`\\${module.exports.sep}`, 'g'), posix.sep);
-          return _.substr(_.indexOf(posix.sep));
+          const _ = StringPrototypeReplace(
+            process.cwd(),
+            new RegExp(`\\${module.exports.sep}`, 'g'),
+            posix.sep
+          );
+          return StringPrototypeSlice(_, StringPrototypeIndexOf(_, posix.sep));
         })();