These new benchmarks better measure rss delta associated with spawning new dart2js isolate.
Also this moves IsolateSpawn heap measurement benchmarks into this group as well because
they are effectively new benchmarks.
Change-Id: Idf31f83b24713932d5ddfa096e23f36ae8195cd2
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/123685
Commit-Queue: Alexander Aprelev <aam@google.com>
Reviewed-by: Martin Kustermann <kustermann@google.com>
Jonas Termansen