test: enhance dot reporter to display failed test names

Add failed test names and execution times to dot reporter output, improving issue identification without verbose reporting.

Fixes: nodejs#51769

lib/internal/test_runner/reporter/dot.js

@@ -1,18 +1,24 @@
 'use strict';
 
+const colors = require('internal/util/colors');
 const {
   MathMax,
 } = primordials;
 
+const failedTestSymbol = '\u2716 ';
+
 module.exports = async function* dot(source) {
   let count = 0;
   let columns = getLineLength();
-  for await (const { type } of source) {
+  let failedTests = [];
+
+  for await (const { type, data } of source) {
     if (type === 'test:pass') {
       yield '.';
     }
     if (type === 'test:fail') {
       yield 'X';
+      failedTests.push(data);
     }
     if ((type === 'test:fail' || type === 'test:pass') && ++count === columns) {
       yield '\n';
@@ -23,6 +29,14 @@ module.exports = async function* dot(source) {
     }
   }
   yield '\n';
+
+  if (failedTests.length > 0) {
+    yield `${colors.red}${failedTestSymbol} failing tests:${colors.white}\n`;
+    for (const test of failedTests) {
+      const message = `${colors.red}${failedTestSymbol} ${test.name} ${colors.gray}(${test.details.duration_ms}ms)\n`;
+      yield message;
+    }
+  }
 };
 
 function getLineLength() {