test_runner: remove stdout and stderr from error

The CLI test runner parses the TAP output from child processes
now and displays it. This commit removes a previous workaround
for displaying child process stdout and stderr when tests
failures occurred.

PR-URL: #45592
Reviewed-By: Michaël Zasso <targos@protonmail.com>
Reviewed-By: Moshe Atlow <moshe@atlow.co.il>

Author: cjihrig

lib/internal/test_runner/runner.js

@@ -234,18 +234,13 @@ function runTestFile(path, root, inspectPort, filesWatcher) {
     runningProcesses.set(path, child);
 
     let err;
-    let stderr = '';
 
     filesWatcher?.watchChildProcessModules(child, path);
 
     child.on('error', (error) => {
       err = error;
     });
 
-    child.stderr.on('data', (data) => {
-      stderr += data;
-    });
-
     if (isUsingInspector()) {
       const rl = createInterface({ input: child.stderr });
       rl.on('line', (line) => {
@@ -266,7 +261,7 @@ function runTestFile(path, root, inspectPort, filesWatcher) {
       subtest.addToReport(ast);
     });
 
-    const { 0: { 0: code, 1: signal }, 1: stdout } = await SafePromiseAll([
+    const { 0: { 0: code, 1: signal } } = await SafePromiseAll([
       once(child, 'exit', { signal: t.signal }),
       child.stdout.toArray({ signal: t.signal }),
     ]);
@@ -279,8 +274,6 @@ function runTestFile(path, root, inspectPort, filesWatcher) {
           __proto__: null,
           exitCode: code,
           signal: signal,
-          stdout: ArrayPrototypeJoin(stdout, ''),
-          stderr,
           // The stack will not be useful since the failures came from tests
           // in a child process.
           stack: undefined,