Fix up NETCoreApp closure validation when assembling runtime packages

[dagood]

In a recent official build binlog, it looks like VerifyClosure isn't running, and its dependency GetClosureFiles doesn't show up at all. This is an important check to ensure shared framework integrity.

[NikolaMilosavljevic]

@jkoritzinsky do you know if this is handled in the new shared FX infra?

[jkoritzinsky]

The is one of the areas I need to still look at. I dont know if this is required since ASP.NET doesn't do anything similar to this. I can look at adding this in the new infra if we still feel it is valuable.

[dagood]

The is one of the areas I need to still look at. I dont know if this is required since ASP.NET doesn't do anything similar to this. I can look at adding this in the new infra if we still feel it is valuable.

@ericstj can help make this call. My understanding is it's pretty important. (I took some efforts to keep it working over time and run it in dotnet/windowsdesktop.)

[ericstj]

This validation helps ensure we're shipping a complete shared framework. It guards against folks taking new dependencies without putting those in the shared framework. It's important and something we should bring back.

[ericstj]

We need to do this for 5.0. It was just exposed that we've introduced cycles into the shared framework because this was missing. @NikolaMilosavljevic or @jkoritzinsky were you planning on fixing this?

[NikolaMilosavljevic]

We need to do this for 5.0. It was just exposed that we've introduced cycles into the shared framework because this was missing. @NikolaMilosavljevic or @jkoritzinsky were you planning on fixing this?

Yes, this is planned. I will work on it soon.

[NikolaMilosavljevic]

Validation in progress - sending PR later today.