Clarification regarding the GitHub Actions pre-submit testing

[Ioi Lam]

One problem with GHA is the frequent false negatives. I think if we can 
reduce that, people will be more willing to trust the results of the GHA 
runs.

[1] Intermittent failures due to machine configuration. Some of those 
are network related (e.g., multi casting). Some are related to user 
privileges (process attachment). Etc.

My feeling is that such environment-sensitive tests are a very minor 
part of the overall tests. Maybe we can have a GHA-specific problem list 
to exclude these tests?

If you are touching these areas, you will need to test your changes 
using other means. However, I think this affects only a small number of 
JDK contributors.

[2] Random build failures, apparently due to toolchain variation. I've 
seen this quite a few times in the past week.

This doesn't seem to be specific to OpenJDK. I assume many other 
projects use GHA as well. How do they handle this situation?

Any other type of issues?

Thanks
- Ioi