Adds extra validation to code collection test.

tests/standalone/io/code_collection_test.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 // Dart test program testing code GC.
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
 
 
 int foo(int x) {
   x = x + 1;
   return x;
 }
 
 
 List<int> bar() {
   // A couple of big allocations trigger GC.
   var l = new List.filled(700000, 7);
   return l;
 }
 
 
 doTest() {
- var i = 0;
-  foo(1);  // Initial call to compile.
+  var i = 0;
+  var ret = foo(1);  // Initial call to compile.
+  print("foo=$ret");
   // Time passes, GC runs, foo's code is dropped.
   var ms = const Duration(milliseconds: 100);
   var t = new Timer.periodic(ms, (timer) {
     i++;
     bar();
     if (i > 1) {
       timer.cancel();
       // foo is called again to make sure we can still run it even after
       // its code has been detached.
-      foo(2);
+      var ret = foo(2);
+      print("foo=$ret");
     }
   });
 }
 
 
 main(List<String> arguments) {
   if (arguments.contains("--run")) {
     doTest();
   } else {
     // Run the test and capture stdout.
     var pr = Process.runSync(Platform.executable,
         ["--collect-code",
-         "--code-collection-interval-in-us=100000",
+         "--code-collection-interval-in-us=0",
          "--old_gen_growth_rate=10",
          "--log-code-drop",
          "--optimization-counter-threshold=-1",
          "--package-root=${Platform.packageRoot}",
          Platform.script.toFilePath(),
          "--run"]);
 
+    Expect.equals(0, pr.exitCode);
+
     // Code drops are logged with --log-code-drop. Look through stdout for the
     // message that foo's code was dropped.
-    var found = false;
+    var count = 0;
     pr.stdout.split("\n").forEach((line) {
+      if (line.contains("foo=2")) {
+        Expect.equals(0, count);
+        count++;
+      }
       if (line.contains("Detaching code") && line.contains("foo")) {
-        found = true;
+        Expect.equals(1, count);
+        count++;
+      }
+      if (line.contains("foo=3")) {
+        Expect.equals(2, count);
+        count++;
       }
     });
-    Expect.isTrue(found);
+    Expect.equals(3, count);
   }
 }