Figure out the best set of assemblies to R2R

[rolfbjarne]

This is a follow-up to #24437.

We're currently adding all the BCL assemblies (and no other assemblies) to the R2R enclosure.

We should look into whether there's a different criteria we should use instead.

Ideas:

• BCL + MAUI + mobile SDK assemblies
• All assemblies that are not debuggable ([dotnet] Add support for ReadyToRun. #24437 (comment))
• Profile and come up with something else based on the results.