Remove fake IUs added to support 2025-06 to 2025-09 updates

[merks]

#333

[jonahgraham]

Is there a strong reason to remove these? I was hoping we could keep them "forever" - we only just removed updating from mars workarounds.

The reason I think we should leave this in is that it is reasonable for users to skip a version or only update once a year, especially as people have to skip releases because of regressions that affect them. With the current staging repos it means that none of the Platform components can ever be updated if they are 2025-06 or before.

With this as available software:

Note that "latest" repos are disabled by me to simulate what will happen when 2026-03 is the "latest". If you have "latest" enabled, it will pick up the now removed transitional packages from there and update fine.

[merks]

One reason is that people expect this to install something meaningful when it’s just empty noise.

@akurtakov
Do you have an opinion? You asked about removing this…

[akurtakov]

My request was provoked by issues like eclipse-platform/eclipse.platform.releng.aggregator#3448 and others similar. The fact that people can have these source features in their target platform without includeSources=true and not have sources at all is quite misleading.
A decision must be taken here - mislead people with target platforms with source features in them to not have sources or make updates version by version. In both cases there will be unhappy people.