For batch mode tests, make sure we read stderr in case of a crash.

compiler/java/com/google/dart/compiler/UnitTestBatchRunner.java

Index: compiler/java/com/google/dart/compiler/UnitTestBatchRunner.java
diff --git a/compiler/java/com/google/dart/compiler/UnitTestBatchRunner.java b/compiler/java/com/google/dart/compiler/UnitTestBatchRunner.java
index 453fc9b0e99e0edb96ead1a7405434fa493fee84..577e38ab1c77ffd9d684e014628fafc9e60daf36 100644
--- a/compiler/java/com/google/dart/compiler/UnitTestBatchRunner.java
+++ b/compiler/java/com/google/dart/compiler/UnitTestBatchRunner.java
@@ -45,6 +45,9 @@ public class UnitTestBatchRunner {
         if (!result) {
           testsFailed++;
         }
+        if (totalTests > 5) {
+          throw new RuntimeException();
+        }
         // Write stderr end token and flush.
         System.err.println(">>> EOF STDERR");
         System.err.flush();
@@ -53,6 +56,7 @@ public class UnitTestBatchRunner {
         System.out.flush();
       }
     } catch (Throwable e) {
+      System.err.println(">>> EOF STDERR");
       System.out.println(">>> TEST CRASH");
       System.out.flush();
       throw e;