Recently perfetto introduced `perfetto::DynamicString` to allow clients
to wrap dynamic event name strings. So that clients don't have to
manually set event name inside trace lambda.

With that:

TRACE_EVENT("cat", nullptr, [&](EventContext ctx) {
  ctx.event().set_name(dynamic_name_str)
});

is simplified to:

TRACE_EVENT("cat", perfetto::DynamicString{dynamic_name_str});

In this change we are making use of perfetto::DynamicString to pass
dynamic event name string.

Change-Id: Ic6b501df67409d6faa4d60b59095ad0e79ce585e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3716473Reviewed-by: Manos Koukoutos <manoskouk@chromium.org>
Commit-Queue: Mohit Saini <mohitms@google.com>
Cr-Commit-Position: refs/heads/main@{#81298}