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

test/unittests/test-utils.h

Index: test/unittests/test-utils.h
diff --git a/test/unittests/test-utils.h b/test/unittests/test-utils.h
index 78283bff572ae31248503f994f9841a9cdae85ca..9950c5a51dded37341409b79cb9ea5e93f90b270 100644
--- a/test/unittests/test-utils.h
+++ b/test/unittests/test-utils.h
@@ -99,7 +99,7 @@ class TestWithZone : public virtual ::testing::Test {
   Zone* zone() { return &zone_; }
 
  private:
-  Zone zone_;
+  ZoneForTesting zone_;
 
   DISALLOW_COPY_AND_ASSIGN(TestWithZone);
 };
@@ -113,7 +113,7 @@ class TestWithIsolateAndZone : public virtual TestWithIsolate {
   Zone* zone() { return &zone_; }
 
  private:
-  Zone zone_;
+  ZoneForTesting zone_;
 
   DISALLOW_COPY_AND_ASSIGN(TestWithIsolateAndZone);
 };