dummy_compiler_test and recursive_import_test are extremely slow on dart2js-linux-d8-hostchecked

[athomas]

Skipping the dummy_compiler_test and recursive_import_test reduces the runtime for the dart2js extra tests by 5 minutes (10 minutes total because they are run in checked and unchecked mode) on the dart2js-linux-d8-hostchecked-try builder.

@sigmundch @efortuna I'm adding Skip for that configuration to the status file for now, is there anything that could be done to make these tests execute faster? Is it important to have them in the CQ?

https://dart-review.googlesource.com/c/sdk/+/6400

[sigmundch]

Thanks @athomas To be honest I think it's fine to suppress it in host-checked. These tests were intended as tests of the compiler API, and I'd be fine just testing this in the VM and not running this on any other configuration (so in the dart2js + d8 config seems rather unnecessary). @johnniwinther - do you agree?

[johnniwinther]

recursive_import_test is not important for CQ nor dart2js+d8. It tests part of the old frontend library loader.

dummy_compiler_test doesn't need to be on CQ but should be run on dart2js+d8. It is not interesting on the vm: It is a self-compilation test and we already know that the vm can run dart2js.

[athomas]

Ok, I will re-enable them for buildbot as soon as we have a way to skip them only for the CQ.

[sigmundch]

OK - I sent https://dart-review.googlesource.com/c/sdk/+/45364 to:
(a) delete recursive_import_test
(b) document better the intent of dummy_compiler_test

I think we should eventually move dummy_compiler_test out of dart2js_extra into our actual unit test suite, and similar to our stacktrace tests, we should invoke d8 directly with it instead.