Run unit tests as single file

[agocke]

The unit tests (hopefully the whole BCL) should be published as single-file executables and run in CI

• Enable publishing and running a test as a single file
• Add CI job
• Port tests/assemblies to be single-file compatible
  • Fix RemoteExecutor to be compatible with Single-File publishing (Disable RemoteExecutor for single-file arcade#6553)
• Verify failures & fixes
  • IsolatedStorage doesn't work from Single-File application IsolatedStorage doesn't work from Single-File application in 5.0 #42265

Tagging subscribers to this area: @agocke, @vitek-karas
See info in area-owners.md if you want to be subscribed.