Avoid some crashes when running without snapshots.

test/cctest/test-debug.cc

Index: test/cctest/test-debug.cc
diff --git a/test/cctest/test-debug.cc b/test/cctest/test-debug.cc
index 9fdabc62893047d57e239e386736760671875bc3..fb397a9c28a8cd2ff72ca77128ba652c4502adcf 100644
--- a/test/cctest/test-debug.cc
+++ b/test/cctest/test-debug.cc
@@ -429,7 +429,7 @@ void CheckDebuggerUnloaded(bool check_functions) {
 
   // Iterate the head and check that there are no debugger related objects left.
   HeapIterator iterator;
-  for (HeapObject* obj = iterator.Next(); obj != NULL; obj = iterator.Next()) {
+  for (HeapObject* obj = iterator.next(); obj != NULL; obj = iterator.next()) {
     CHECK(!obj->IsDebugInfo());
     CHECK(!obj->IsBreakPointInfo());