Use hash map for event handler file descriptor map

tests/standalone/src/ProcessStderrTest.dart

Index: tests/standalone/src/ProcessStderrTest.dart
diff --git a/tests/standalone/src/ProcessStderrTest.dart b/tests/standalone/src/ProcessStderrTest.dart
index 17637eb008cf0a6a343d85e0c9830bfe425c518b..e2b1d530e0a535bff88fe9e960cf39fbbd576567 100644
--- a/tests/standalone/src/ProcessStderrTest.dart
+++ b/tests/standalone/src/ProcessStderrTest.dart
@@ -12,7 +12,7 @@
 #library("ProcessStderrTest");
 #source("ProcessTestUtil.dart");
 
-void test(Process process) {
+void test(Process process, int expectedExitCode) {
   // Wait for the process to start and then interact with it.
   process.startHandler = () {
     List<int> data = "ABCDEFGHI\n".charCodes();
@@ -49,12 +49,16 @@ void test(Process process) {
     output.close();
     input.dataHandler = readData;
   };
+
+  process.exitHandler = (exitCode) {
+    Expect.equals(expectedExitCode, exitCode);
+  };
 }
 
 main() {
   // Run the test using the process_test binary.
   test(new Process.start(getProcessTestFileName(),
-                         const ["1", "1", "99", "0"]));
+                         const ["1", "1", "99", "0"]), 99);
 
   // Run the test using the dart binary with an echo script.
   // The test runner can be run from either the root or from runtime.
@@ -63,5 +67,5 @@ main() {
     scriptFile = new File("../tests/standalone/src/ProcessStdIOScript.dart");
   }
   Expect.isTrue(scriptFile.existsSync());
-  test(new Process.start(getDartFileName(), [scriptFile.name, "1"]));
+  test(new Process.start(getDartFileName(), [scriptFile.name, "1"]), 0);
 }