`ci-test.sh` may timeout in 6h

[qinsoon]

We have a script .github/scripts/ci-test.sh that allows mmtk-core to run. As Github runner has a limit of 6h timeout, the script needs to finish in 6h. However, our ci-test.sh is always close to the 6h limit, and sometimes just times out.

What we could do:

• Split the script into multiple scripts, and call them in mmtk-core's binding tests.
• Try use workflow_dispatch, and allow mmtk-core to dispatch to a workflow in mmtk-julia, and we can use our normal test workflow (running multiple tests in parallel).

[qinsoon]

https://github.com/mmtk/mmtk-julia/pull/95 increases the CI time a lot.

test	Before (e.g. https://github.com/mmtk/mmtk-julia/pull/92 in https://github.com/mmtk/mmtk-julia/actions/runs/5932643503/usage)	After (https://github.com/mmtk/mmtk-julia/pull/95 in https://github.com/mmtk/mmtk-julia/actions/runs/5994092545/usage?pr=95)
binding-tests (Immix) / build-debug	29m 3s	46m 45s
binding-tests (StickyImmix) / build-debug	27m 47s	31m 29s
binding-tests (Immix) / build-test-other	2h 36m 40s	2h 32m 56s
binding-tests (Immix) / build-test-stdlib	3h 35m 55s	5h 33m 4s
binding-tests (StickyImmix) / build-test-other	2h 33m 9s	3h 11m 33s
binding-tests (StickyImmix) / build-test-stdlib	3h 4m 59s	5h 47m 49s

I haven't tried yet, but it is very likely ci-test.sh will time out for MMTk core CI. Consider run fewer tests for MMTk core, or separate into two jobs.

[qinsoon]

Done in https://github.com/mmtk/mmtk-julia/pull/97. We only run a subset of the tests. We should be fine now.