[llvm-branch-commits] [CI] Migrate monolithic-linux script to sccache (PR #149195)

[Aiden Grossman via llvm-branch-commits]

https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/149195

This is in preparation for migrating to Google Cloud Storage (GCS) based
caching soon which is only supported by sccache.