Fix reporting of QUnit todo tests

The update to js-reporters 2.1.0 in the previous commit has fixed
the most important problem, which is the build status reported
by the `runEnd` event, handled via "_report" submission.

However, the todo tests were still printed as errors in the output
which is confusing.

Before:

```
[Windows 8, Chrome 91.0] Error: "test.todo.each [0]" failed
  Expected: true
  Actual: false
[Windows 8, Chrome 91.0] Passed: 332 tests, 321 passed, 0 failed, 7 skipped; ran for 1255ms
```

After:

```
[Windows 10, Firefox 88.0] Passed: 332 tests, 321 passed, 0 failed, 7 skipped; ran for 1910ms
```

Fixes browserstack#247.

Author: Krinkle

lib/server.js

@@ -387,17 +387,27 @@ exports.Server = function Server(bsClient, workers, config, callback) {
 
       logger.trace('[%s] _progress', worker.id, CircularJSON.stringify(query));
 
-      if (query && query.test && query.test.errors) {
+      if (query && query.test) {
+        // Include all tests in the report
         var browserReport = getBrowserReport(browserInfo);
         browserReport.tests.push(query.test || {});
 
-        query.test.errors.forEach(function(error) {
-          logger.info('[%s] ' + chalk.red('Error:'), browserInfo, formatTraceback({
-            error: error,
-            testName: query.test.name,
-            suiteName: query.test.suiteName
-          }));
-        });
+        // Only print errors of failed tests
+        // (errors from todo tests are expected and will not be reported as
+        // "failed" to the "_report" handler either, so printing them here
+        // would create a confusing output with error printed but a success
+        // status at the end)
+        // https://github.com/browserstack/browserstack-runner/issues/247
+        if (query.test.errors && query.test.status !== 'todo') {
+          query.test.errors.forEach(function(error) {
+            logger.info('[%s] ' + chalk.red('Error:'), browserInfo, formatTraceback({
+              testName: query.test.name,
+              suiteName: query.test.suiteName,
+              status: query.test.status,
+              error: error
+            }));
+          });
+        }
       }
       response.end();
     },