Remove obsolete debug code and add new one.

src/mark-compact.h

Index: src/mark-compact.h
diff --git a/src/mark-compact.h b/src/mark-compact.h
index 9cdb46a4f9df60b35845117c020ec604f61555b6..a92644e98c0b9c1b1f9daf01f2024350dfd2f9f0 100644
--- a/src/mark-compact.h
+++ b/src/mark-compact.h
@@ -423,10 +423,6 @@ class CodeFlusher {
     if (GetNextCandidate(shared_info) == NULL) {
       SetNextCandidate(shared_info, shared_function_info_candidates_head_);
       shared_function_info_candidates_head_ = shared_info;
-    } else {
-      // TODO(mstarzinger): Active in release mode to flush out problems.
-      // Should be turned back into an ASSERT or removed completely.
-      CHECK(ContainsCandidate(shared_info));
     }
   }
 
@@ -438,8 +434,6 @@ class CodeFlusher {
     }
   }
 
-  bool ContainsCandidate(SharedFunctionInfo* shared_info);
-
   void EvictCandidate(SharedFunctionInfo* shared_info);
   void EvictCandidate(JSFunction* function);