[release/6.0.1xx] SDK diff exclusions - backport

[NikolaMilosavljevic]

Backport of #15650

Fixes dotnet/source-build#3266

Infrastructure change.

• Adds support for exclusions in SDK diffing tests.
• Fixes the issue with version abstraction by moving it to WriteTarballFileList, so exclusions are even possible - this makes the diffing infra the same as in 7.0 and 8.0
• Updates the exclusion list, compared to 8.0 and 7.0 versions, to account for differences in 6.0 codebase - TestHost is the only test-host directory, which also has some resources in LOC sub-directories