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

test/cctest/compiler/test-loop-analysis.cc

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/access-builder.h"
 #include "src/compiler/common-operator.h"
 #include "src/compiler/graph.h"
 #include "src/compiler/graph-visualizer.h"
 #include "src/compiler/js-graph.h"
 #include "src/compiler/js-operator.h"
@@ skipping 109 matching lines @@
     end->ReplaceInput(0, ret);
     return ret;
   }
 
   LoopTree* GetLoopTree() {
     if (loop_tree == NULL) {
       if (FLAG_trace_turbo_graph) {
         OFStream os(stdout);
         os << AsRPO(graph);
       }
-      Zone zone;
+      Zone zone(main_isolate()->allocator());
       loop_tree = LoopFinder::BuildLoopTree(&graph, &zone);
     }
     return loop_tree;
   }
 
   void CheckLoop(Node** header, int header_count, Node** body, int body_count) {
     LoopTree* tree = GetLoopTree();
     LoopTree::Loop* loop = tree->ContainingLoop(header[0]);
     CHECK(loop);
 
@@ skipping 873 matching lines @@
 TEST(LaManyNested_62) { RunManyNestedLoops_i(62); }
 TEST(LaManyNested_63) { RunManyNestedLoops_i(63); }
 TEST(LaManyNested_64) { RunManyNestedLoops_i(64); }
 
 
 TEST(LaPhiTangle) { LoopFinderTester t; }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8