test_runner: hide failing tests title when all tests pass

PR-URL: https://github.com/nodejs/node/pull/47370
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Benjamin Gruenbaum <benjamingr@gmail.com>
Reviewed-By: Luigi Pinca <luigipinca@gmail.com>

lib/internal/test_runner/reporter/spec.js

@@ -124,6 +124,10 @@ class SpecReporter extends Transform {
     callback(null, this.#handleEvent({ type, data }));
   }
   _flush(callback) {
+    if (this.#failedTests.length === 0) {
+      callback(null, '');
+      return;
+    }
     const results = [`\n${colors['test:fail']}${symbols['test:fail']}failing tests:${white}\n`];
     for (let i = 0; i < this.#failedTests.length; i++) {
       ArrayPrototypePush(results, this.#formatTestReport(

test/message/test_runner_spec_reporter_successful.js

@@ -0,0 +1,6 @@
+// Flags: --no-warnings --test-reporter=spec
+'use strict';
+require('../common');
+const { it } = require('node:test');
+
+it('should pass', () => {});

test/message/test_runner_spec_reporter_successful.out

@@ -0,0 +1,9 @@
+* should pass *(*ms)*
+*tests 1*
+*suites 0*
+*pass 1*
+*fail 0*
+*cancelled 0*
+*skipped 0*
+*todo 0*
+*duration_ms *