[DevOps] Investigate MacOs Build from Source in K pipeline (backends & downstream)

[F-WRunTime]

• haskell-backend
• llvm-backend
• K

Revisit the changes introduced a few months dropping Mac builds to rely on Mac.
Decide to?

• Drop Mac src builds / support
• Keep src builds and investigate the above targets for src building and testing to avoid uncaught issues in K on release.

[jberthold]

Discussed with @tothtamas28 and @palinatolmach .
The LLVM backend CI does not use a Mac build at all so it might be OK to drop MacOS homebrew packaging but we should coordinate with Pi^2.
Whether we can simply ignore the failing job and continue the release workflow is unknown at the moment.