Fix timeouts in standalone/io/TestRunnerTest by increasing timeout. Fix a few errors in test_runne…

tools/testing/dart/test_runner.dart

Index: tools/testing/dart/test_runner.dart
diff --git a/tools/testing/dart/test_runner.dart b/tools/testing/dart/test_runner.dart
index 2615303f8fe9a52d4ef85abf05666564610d772c..1eeb00e8268906b3b80c9393f8934e3f6068534e 100644
--- a/tools/testing/dart/test_runner.dart
+++ b/tools/testing/dart/test_runner.dart
@@ -506,6 +506,8 @@ class RunningProcess {
   /** Which command of [testCase.commands] is currently being executed. */
   int currentStep;
 
+  static final int kErrorStartingProcess = -171717;  // Chosen arbitrarily.
+
   RunningProcess(TestCase this.testCase,
       [this.allowRetries = false, this.processQueue]);
 
@@ -600,6 +602,7 @@ class RunningProcess {
     }
     process = new Process.start(command.executable, command.arguments);
     process.onExit = exitHandler;
+    process.onError = (error) { exitHandler(kErrorStartingProcess); };
     startTime = new Date.now();
     InputStream stdoutStream = process.stdout;
     InputStream stderrStream = process.stderr;
@@ -609,7 +612,10 @@ class RunningProcess {
         makeReadHandler(stdoutStringStream, stdout);
     stderrStringStream.onLine =
         makeReadHandler(stderrStringStream, stderr);
-    timeoutTimer = new Timer(1000 * testCase.timeout, timeoutHandler);
+    if (timeoutTimer == null) {
+      // Create one timeout timer when starting test case, remove it at end.
+      timeoutTimer = new Timer(1000 * testCase.timeout, timeoutHandler);
+    }
   }
 
   void timeoutHandler(Timer unusedTimer) {
@@ -1101,8 +1107,9 @@ class ProcessQueue {
       }
       if (test.usesWebDriver && _needsSelenium && !_isSeleniumAvailable) {
         // The server is not ready to run Selenium tests. Put the test back in
-        // the queue.
-        _tests.addFirst(test);
+        // the queue.  Avoid spin-polling by using a timeout.
+        _tests.add(test);
+        new Timer(1000, (timer) {_tryRunTest();});  // Don't lose a process.
         return;
       }
       if (_verbose) {