Revert "Dispose Isolate at end of cctest."

Things work locally, only the waterfall is unhappy for some arcane reason.
Investigating...

TBR=bmeurer@chromium.org

Review URL: https://codereview.chromium.org/133193006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@19049 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

test/cctest/cctest.h

@@ -131,7 +131,8 @@ class CcTest {
       v8::Isolate* isolate = CcTest::isolate());
 
   static void TearDown() {
-    if (isolate_ != NULL) isolate_->Dispose();
+    // TODO(svenpanne) Enable this when our cctests are fixed.
+    // if (isolate_ != NULL) isolate_->Dispose();
   }
 
  private: