test: add error only reporter for node:test

This commit introduces a node:test reporter to the common utils.
This reporter can be used to silence output other than errors
from node:test. This is useful because in Node's own test suite,
the output of node:test is included in the output of the
Python test runner.

Refs: nodejs#49120

test/common/test-error-reporter.js

@@ -0,0 +1,35 @@
+'use strict';
+const { relative } = require('node:path');
+const { inspect } = require('node:util');
+const cwd = process.cwd();
+
+module.exports = async function* errorReporter(source) {
+  for await (const event of source) {
+    if (event.type === 'test:fail') {
+      const { name, details, line, column, file } = event.data;
+      let { error } = details;
+
+      if (error?.failureType === 'subtestsFailed') {
+        // In the interest of keeping things concise, skip failures that are
+        // only due to nested failures.
+        continue;
+      }
+
+      if (error?.code === 'ERR_TEST_FAILURE') {
+        error = error.cause;
+      }
+
+      const output = [
+        `Test failure: '${name}'`,
+      ];
+
+      if (file) {
+        output.push(`Location: ${relative(cwd, file)}:${line}:${column}`);
+      }
+
+      output.push(inspect(error));
+      output.push('\n');
+      yield output.join('\n');
+    }
+  }
+};

test/parallel/test-runner-cli-concurrency.js

@@ -1,3 +1,4 @@
+// Flags: --test-reporter=./test/common/test-error-reporter.js
 'use strict';
 require('../common');
 const fixtures = require('../common/fixtures');