chore: simplified Jest & babel config

Author: JoshuaKGoldberg

Diff for: babel.config.js

@@ -1,7 +1,3 @@
 module.exports = {
     presets: [["@babel/preset-env", { targets: { node: "current" } }], "@babel/preset-typescript"],
-    plugins: [
-        "@babel/plugin-proposal-nullish-coalescing-operator",
-        "@babel/plugin-proposal-optional-chaining",
-    ],
 };

Diff for: package.json

@@ -71,7 +71,7 @@
         "prettier": "prettier \"./src/*.{js,json,ts,xml,yaml}\" \"./src/**/*.{js,json,ts,xml,yaml}\" --ignore-path .prettierignore",
         "prettier:write": "npm run prettier -- --write",
         "test": "jest",
-        "test:ci": "NODE_OPTIONS=--experimental-vm-modules jest --coverage --maxWorkers=2",
+        "test:ci": "jest --coverage --maxWorkers=2",
         "tsc": "tsc"
     },
     "version": "2.10.1"