New SuperIlc command "compile-framework" and some fixes (dotnet/coreclr#26804)

New SuperIlc command "compile-framework" and some fixes (dotnet/coreclr#26804)

1) New command "compile-framework" does just what it says on the tin.
My thinking is that I'll use this option to build the CPAOT
framework during product build in the envisioned pipeline. I have
added hard-coded exclusions for assemblies that fail to build right
now - about half of them aren't interesting as framework assemblies
(e.g. R2RDump.dll), some other fail with IBC bugs and one other bug
I'm about to investigate.

2) Based on JanV's suggestion I have added a somewhat hacky logic
to exclude the "testhost" folder when building the entire Pridotnet/coreclr#1
test tree. I'm open to suggestions how to tackle this in a cleaner
manner, I have shared my thoughts on the subject in code comments
next to the problematic spots.

Thanks

Tomas

Commit migrated from https://github.com/dotnet/coreclr/commit/ddbdf5739bdfbcc94b245090806371afb3dbbef5