Update test framework: fix run_tests.py to support all test files, add auto-import-check for test files

node_modules/import-in-the-middle/test/fixtures/module-exports-cjs-shim.mjs

@@ -0,0 +1,7 @@
+// Regression test for https://github.com/nodejs/import-in-the-middle/issues/196
+
+export default function foo () {
+  // do nothing
+}
+
+export { foo as 'module.exports' }