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

src/wasm/wasm-js.cc

Index: src/wasm/wasm-js.cc
diff --git a/src/wasm/wasm-js.cc b/src/wasm/wasm-js.cc
index 11bcdb86a1147c638928730b6f88d6fd8dea010c..83009d7c81def5acbd56bc711fc5f2c5528db216 100644
--- a/src/wasm/wasm-js.cc
+++ b/src/wasm/wasm-js.cc
@@ -86,7 +86,7 @@ void VerifyModule(const v8::FunctionCallbackInfo<v8::Value>& args) {
   RawBuffer buffer = GetRawBufferArgument(thrower, args);
   if (thrower.error()) return;
 
-  i::Zone zone;
+  i::Zone zone(isolate->allocator());
   internal::wasm::ModuleResult result =
       internal::wasm::DecodeWasmModule(isolate, &zone, buffer.start, buffer.end,
                                        true, internal::wasm::kWasmOrigin);
@@ -111,7 +111,7 @@ void VerifyFunction(const v8::FunctionCallbackInfo<v8::Value>& args) {
   {
     // Verification of a single function shouldn't allocate.
     i::DisallowHeapAllocation no_allocation;
-    i::Zone zone;
+    i::Zone zone(isolate->allocator());
     result = internal::wasm::DecodeWasmFunction(isolate, &zone, nullptr,
                                                 buffer.start, buffer.end);
   }
@@ -170,7 +170,7 @@ void InstantiateModuleCommon(const v8::FunctionCallbackInfo<v8::Value>& args,
 
   // Decode but avoid a redundant pass over function bodies for verification.
   // Verification will happen during compilation.
-  i::Zone zone;
+  i::Zone zone(isolate->allocator());
   internal::wasm::ModuleResult result = internal::wasm::DecodeWasmModule(
       isolate, &zone, start, end, false, origin);
 
@@ -209,7 +209,7 @@ void InstantiateModuleFromAsm(const v8::FunctionCallbackInfo<v8::Value>& args) {
   }
 
   i::Factory* factory = isolate->factory();
-  i::Zone zone;
+  i::Zone zone(isolate->allocator());
   Local<String> source = Local<String>::Cast(args[0]);
   i::Handle<i::Script> script = factory->NewScript(Utils::OpenHandle(*source));
   i::ParseInfo info(&zone, script);