fix(webpack): add virtualEntry before main entry

fixes running with the JSC runtime, fixes #9469

packages/webpack5/src/helpers/chain.ts

@@ -0,0 +1,24 @@
+import { ChainedSet } from 'webpack-chain';
+
+/**
+ * Helper to insert values after a specific item in a ChainedSet.
+ *
+ * @param chainedSet
+ * @param after
+ * @param itemToAdd
+ */
+export function chainedSetAddAfter(
+	chainedSet: ChainedSet<any>,
+	after: any,
+	itemToAdd: any
+) {
+	const values = chainedSet.values();
+
+	if (values.includes(after)) {
+		values.splice(values.indexOf(after) + 1, 0, itemToAdd);
+	} else {
+		values.push(itemToAdd);
+	}
+
+	chainedSet.clear().merge(values);
+}