Simplify the enqueuing of tests from all test suites

tools/test-runtime.dart

Index: tools/test-runtime.dart
diff --git a/tools/test-runtime.dart b/tools/test-runtime.dart
index 95c24d4bad5147eaf0b557498ad43ef3df43bb09..21932743d7145481538491d349cd2836395cb31f 100755
--- a/tools/test-runtime.dart
+++ b/tools/test-runtime.dart
@@ -72,25 +72,21 @@ main() {
     print(Strings.join(output_words, ' '));
   }
 
-  var configurationIterator = configurations.iterator;
-  void enqueueConfiguration(ProcessQueue queue) {
-    if (!configurationIterator.moveNext()) return;
-
-    var conf = configurationIterator.current;
+  var testSuites = new List<TestSuite>();
+  for (var conf in configurations) {
     if (selectors.containsKey('co19')) {
-      queue.addTestSuite(new Co19TestSuite(conf));
+      testSuites.add(new Co19TestSuite(conf));
     }
     if (conf['runtime'] == 'vm' && selectors.containsKey('vm')) {
       // vm tests contain both cc tests (added here) and dart tests (added in
       // [TEST_SUITE_DIRECTORIES]).
-      queue.addTestSuite(new VMTestSuite(conf));
+      testSuites.add(new VMTestSuite(conf));
     }
 
     for (final testSuiteDir in TEST_SUITE_DIRECTORIES) {
       final name = testSuiteDir.filename;
       if (selectors.containsKey(name)) {
-        queue.addTestSuite(
-            new StandardTestSuite.forDirectory(conf, testSuiteDir));
+        testSuites.add(new StandardTestSuite.forDirectory(conf, testSuiteDir));
       }
     }
   }
@@ -112,7 +108,7 @@ main() {
       progressIndicator,
       startTime,
       printTiming,
-      enqueueConfiguration,
+      testSuites,
       () => terminateHttpServer(),
       verbose,
       listTests);