src: set arraybuffer_untransferable_private_symbol

for `ArrayBuffer` whose buffers are not own by `BackingStore`. This
would help us avoid problem with the new V8 BackingStore API where new
`ArrayBuffer` is allocated at the same place of previous `ArrayBuffer`
that is still being tracked in `BackingStore` table.

PR-URL: #31053
Refs: #31052
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Rich Trott <rtrott@gmail.com>

src/node_buffer.cc

@@ -1213,6 +1213,10 @@ void Initialize(Local<Object> target,
     // TODO(thangktran): drop this check when V8 is pumped to 8.0 .
     if (!array_buffer->IsExternal())
       array_buffer->Externalize(array_buffer->GetBackingStore());
+    array_buffer->SetPrivate(
+        env->context(),
+        env->arraybuffer_untransferable_private_symbol(),
+        True(env->isolate())).Check();
     CHECK(target
               ->Set(env->context(),
                     FIXED_ONE_BYTE_STRING(env->isolate(), "zeroFill"),

src/node_http2.cc

@@ -578,6 +578,9 @@ Http2Session::Http2Session(Environment* env,
     // TODO(thangktran): drop this check when V8 is pumped to 8.0 .
     if (!ab->IsExternal())
       ab->Externalize(ab->GetBackingStore());
+    ab->SetPrivate(env->context(),
+                   env->arraybuffer_untransferable_private_symbol(),
+                   True(env->isolate())).Check();
     js_fields_ab_.Reset(env->isolate(), ab);
     Local<Uint8Array> uint8_arr =
         Uint8Array::New(ab, 0, kSessionUint8FieldCount);