Tests for Dart Isolates

Using

Compile using: /usr/bin/dart --enable-isolate-groups compile aot-snapshot bin/main.dart

Results:

run on: Dell 5400 Chromebook i7-8665U in a Debian10 Crostini container

Dart SDK version: 2.12.0-110.0.dev (dev) (Unknown timestamp) on "linux_x64")

The dot basic test

Baseline:

/usr/lib/dart/bin/dartaotruntime  bin/main.aot 10000
RSS current:10256384 max:10256384
....................................................................................................time: 20460
RSS current:67088384 max:71393280

With improvements from #36097

/usr/lib/dart/bin/dartaotruntime --enable-isolate-groups  bin/main.aot 10000
RSS current:10403840 max:10403840
....................................................................................................time: 3485
RSS current:27586560 max:28921856

Note: Used dartaotruntime from an old Dart SDK inside an old Flutter 1.20 I had already installed as couldn't find