[vm/concurrency] Make Dart_CreateIsolateInGroup() return an error if --enable-isolate-groups is not passed

This is a safeguard to prevent accidental uses of this API by embedders
if those embedders do not pass --enable-isolate-groups.

Issue https://github.com/dart-lang/sdk/issues/36097

TEST=runtime/tests/vm/dart/isolates/dart_api_create_lightweight_isolate_test.dart

Change-Id: Iba667f0e9fbbb33de963fabb80da546df794257c
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/174404
Commit-Queue: Martin Kustermann <kustermann@google.com>
Reviewed-by: Alexander Aprelev <aam@google.com>

https://dart.googlesource.com/sdk/+/33b7721c51ad499f8a6adf9c0366ca1bfcbbe84b
1 file changed
tree: 1fdd0029d9bff988a323afa7668f815f66549731
  1. commits.json