Expose a lower bound of malloc'd memory via heap statistics

test/cctest/test-ast.cc

Index: test/cctest/test-ast.cc
diff --git a/test/cctest/test-ast.cc b/test/cctest/test-ast.cc
index 49e44eb7b9e6a74d7d76348676fc44fb07c953a6..e785c76bbcb67e5a82f70b5b07524704484c9864 100644
--- a/test/cctest/test-ast.cc
+++ b/test/cctest/test-ast.cc
@@ -38,7 +38,7 @@ TEST(List) {
   List<AstNode*>* list = new List<AstNode*>(0);
   CHECK_EQ(0, list->length());
 
-  Zone zone;
+  ZoneForTesting zone;
   AstValueFactory value_factory(&zone, 0);
   AstNodeFactory factory(&value_factory);
   AstNode* node = factory.NewEmptyStatement(RelocInfo::kNoPosition);