Enable ergonomic brand checks (#priv in) by default (#13554)

* Enable ergonomic brand checks by default in `@babel/parser`

* Enable ergonomic brand checks by default in `preset-env`

* Fix error position

* Update Babel 8 tests

scripts/parser-tests/test262/index.js

@@ -152,7 +152,6 @@ const ignoredFeatures = [
 const ignoredTests = ["built-ins/RegExp/", "language/literals/regexp/"];
 
 const featuresToPlugins = {
-  "class-fields-private-in": "privateIn",
   "class-static-block": "classStaticBlock",
   "top-level-await": "topLevelAwait",
   "import-assertions": "importAssertions",