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

node_modules/yargs/yargs.mjs

@@ -0,0 +1,10 @@
+// TODO: consolidate on using a helpers file at some point in the future, which
+// is the approach currently used to export Parser and applyExtends for ESM:
+import pkg from './build/index.cjs';
+const {applyExtends, cjsPlatformShim, Parser, processArgv, Yargs} = pkg;
+Yargs.applyExtends = (config, cwd, mergeExtends) => {
+  return applyExtends(config, cwd, mergeExtends, cjsPlatformShim);
+};
+Yargs.hideBin = processArgv.hideBin;
+Yargs.Parser = Parser;
+export default Yargs;