test(@angular/cli): skip npm version limit E2E on Windows

Due to the setup of the Windows CI image, replacing npm will fail.

(cherry picked from commit efeebdb)

Author: clydin

tests/legacy-cli/e2e/tests/misc/npm-7.ts

@@ -10,6 +10,11 @@ export default async function() {
     return;
   }
 
+  // Windows CI fails with permission errors when trying to replace npm
+  if (process.platform.startsWith('win')) {
+    return;
+  }
+
   const currentDirectory = process.cwd();
   try {
     // Install version 7.x