test: use v8 Default Allocator in cctest fixture

This commit updates the node_test_fixture to use
v8::ArrayBuffer::Allocator::NewDefaultAllocator() and removes the custom
allocator.

PR-URL: #17366
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Timothy Gu <timothygu99@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Ben Noordhuis <info@bnoordhuis.nl>

test/cctest/node_test_fixture.h

@@ -9,21 +9,6 @@
 #include "v8.h"
 #include "libplatform/libplatform.h"
 
-class ArrayBufferAllocator : public v8::ArrayBuffer::Allocator {
- public:
-  virtual void* Allocate(size_t length) {
-    return AllocateUninitialized(length);
-  }
-
-  virtual void* AllocateUninitialized(size_t length) {
-    return calloc(length, 1);
-  }
-
-  virtual void Free(void* data, size_t) {
-    free(data);
-  }
-};
-
 struct Argv {
  public:
   Argv() : Argv({"node", "-p", "process.version"}) {}
@@ -75,7 +60,6 @@ class NodeTestFixture : public ::testing::Test {
 
  protected:
   v8::Isolate::CreateParams params_;
-  ArrayBufferAllocator allocator_;
   v8::Isolate* isolate_;
 
   ~NodeTestFixture() {
@@ -87,7 +71,7 @@ class NodeTestFixture : public ::testing::Test {
     platform_ = new node::NodePlatform(8, &current_loop, nullptr);
     v8::V8::InitializePlatform(platform_);
     v8::V8::Initialize();
-    params_.array_buffer_allocator = &allocator_;
+    params_.array_buffer_allocator = allocator_.get();
     isolate_ = v8::Isolate::New(params_);
   }
 
@@ -105,6 +89,8 @@ class NodeTestFixture : public ::testing::Test {
 
  private:
   node::NodePlatform* platform_ = nullptr;
+  std::unique_ptr<v8::ArrayBuffer::Allocator> allocator_{
+      v8::ArrayBuffer::Allocator::NewDefaultAllocator()};
 };
 
 #endif  // TEST_CCTEST_NODE_TEST_FIXTURE_H_