fixup: remove branch entirely instead of asserting

See review comments on #22273 for rationale.

wchargin-branch: normalizeString-dead-branch

Author: wchargin

lib/path.js

@@ -21,10 +21,7 @@
 
 'use strict';
 
-const {
-  ERR_ASSERTION,
-  ERR_INVALID_ARG_TYPE
-} = require('internal/errors').codes;
+const { ERR_INVALID_ARG_TYPE } = require('internal/errors').codes;
 const {
   CHAR_UPPERCASE_A,
   CHAR_LOWERCASE_A,
@@ -80,23 +77,16 @@ function normalizeString(path, allowAboveRoot, separator, isPathSeparator) {
             res.charCodeAt(res.length - 2) !== CHAR_DOT) {
           if (res.length > 2) {
             const lastSlashIndex = res.lastIndexOf(separator);
-            if (lastSlashIndex !== res.length - 1) {
-              if (lastSlashIndex === -1) {
-                res = '';
-                lastSegmentLength = 0;
-              } else {
-                res = res.slice(0, lastSlashIndex);
-                lastSegmentLength = res.length - 1 - res.lastIndexOf(separator);
-              }
-              lastSlash = i;
-              dots = 0;
-              continue;
+            if (lastSlashIndex === -1) {
+              res = '';
+              lastSegmentLength = 0;
             } else {
-              throw new ERR_ASSERTION(
-                'invariant violation: unreachable: ' +
-                  JSON.stringify({ path, allowAboveRoot, separator })
-              );
+              res = res.slice(0, lastSlashIndex);
+              lastSegmentLength = res.length - 1 - res.lastIndexOf(separator);
             }
+            lastSlash = i;
+            dots = 0;
+            continue;
           } else if (res.length === 2 || res.length === 1) {
             res = '';
             lastSegmentLength = 0;