Run tests in a native Node.js ESM environment (#13966)

eslint/babel-eslint-parser/test/package.json

@@ -0,0 +1 @@
+{ "type": "module" }

eslint/babel-eslint-plugin-development-internal/test/rules/package.json

@@ -0,0 +1 @@
+{ "type": "module" }

eslint/babel-eslint-plugin-development/test/rules/package.json

@@ -0,0 +1 @@
+{ "type": "module" }

eslint/babel-eslint-plugin/test/rules/package.json

@@ -0,0 +1 @@
+{ "type": "module" }

eslint/babel-eslint-tests/test/fixtures/package.json

@@ -0,0 +1 @@
+{ "type": "commonjs" }

eslint/babel-eslint-tests/test/helpers/verifyAndAssertMessages.js

@@ -31,7 +31,7 @@ export default function verifyAndAssertMessages(
           "../../../babel-eslint-shared-fixtures/config/babel.config.js",
         ),
       },
-      ...overrideConfig?.parserOptions,
+      ...(overrideConfig && overrideConfig.parserOptions),
     },
   });
 

eslint/babel-eslint-tests/test/package.json

@@ -0,0 +1 @@
+{ "type": "module" }