Change the superclass of the translatable version of
junit.framework.AssertionFailedError to match the JVM version,
for consistency when catching java.lang.AssertionError in
testing tools.

Fixes issue 6863.

Review at http://gwt-code-reviews.appspot.com/1565803

Review by: rjrjr@google.com

git-svn-id: https://google-web-toolkit.googlecode.com/svn/trunk@10694 8db76d5a-ed1c-0410-87a9-c151d255dfc7
diff --git a/user/super/com/google/gwt/junit/translatable/junit/framework/AssertionFailedError.java b/user/super/com/google/gwt/junit/translatable/junit/framework/AssertionFailedError.java
index c42a09a..986d67a 100644
--- a/user/super/com/google/gwt/junit/translatable/junit/framework/AssertionFailedError.java
+++ b/user/super/com/google/gwt/junit/translatable/junit/framework/AssertionFailedError.java
@@ -18,7 +18,7 @@
 /**
  * Translatable version of JUnit's <code>AssertionFailedError</code>.
  */
-public class AssertionFailedError extends Error {
+public class AssertionFailedError extends AssertionError {
 
   public AssertionFailedError() {
   }