Always create a CppHeap at isolate creation

With the new V8 API, the CppHeap should be provided during Isolate
initialization.

Author: gahaas

src/api/environment.cc

@@ -304,6 +304,10 @@ Isolate* NewIsolate(Isolate::CreateParams* params,
                     MultiIsolatePlatform* platform,
                     const SnapshotData* snapshot_data,
                     const IsolateSettings& settings) {
+  if (params->cpp_heap == nullptr) {
+    params->cpp_heap =
+        v8::CppHeap::Create(platform, v8::CppHeapCreateParams{{}}).release();
+  }
   Isolate* isolate = Isolate::Allocate();
   if (isolate == nullptr) return nullptr;
 

test/cctest/test_environment.cc

@@ -624,6 +624,9 @@ TEST_F(NodeZeroIsolateTestFixture, CtrlCWithOnlySafeTerminationTest) {
   // Allocate and initialize Isolate.
   v8::Isolate::CreateParams create_params;
   create_params.array_buffer_allocator = allocator.get();
+  create_params.cpp_heap =
+      v8::CppHeap::Create(platform.get(), v8::CppHeapCreateParams{{}})
+          .release();
   v8::Isolate* isolate = v8::Isolate::Allocate();
   CHECK_NOT_NULL(isolate);
   platform->RegisterIsolate(isolate, &current_loop);