Improve @babel/runtime esm stability (#12883)

test/runtime-integration/webpack-4/package.json

@@ -0,0 +1,9 @@
+{
+  "name": "@babel-internal/runtime-integration-webpack-4",
+  "private": true,
+  "devDependencies": {
+    "@babel/runtime": "workspace:*",
+    "webpack": "^4.46.0",
+    "webpack-cli": "^4.5.0"
+  }
+}

test/runtime-integration/webpack-4/webpack.absolute.config.js

@@ -0,0 +1,13 @@
+const path = require("path");
+
+module.exports = {
+  mode: "development",
+
+  entry: path.join(__dirname, "../src/absolute/main-esm.mjs"),
+  output: {
+    path: __dirname,
+    filename: "output-absolute.js",
+  },
+
+  devtool: false,
+};

test/runtime-integration/webpack-4/webpack.config.js

@@ -0,0 +1,13 @@
+const path = require("path");
+
+module.exports = {
+  mode: "development",
+
+  entry: path.join(__dirname, "../src/main-esm.mjs"),
+  output: {
+    path: __dirname,
+    filename: "output.js",
+  },
+
+  devtool: false,
+};