[llvm-branch-commits] [CI] Remove ccache from Linux CI Container (PR #149197)

[Aiden Grossman via llvm-branch-commits]

https://github.com/boomanaiden154 created https://github.com/llvm/llvm-project/pull/149197

This patch removes ccache from the Linux CI container. It is no longer
needed after migrating the monolithic-linux.sh script. The other two
upstream users of this container, namely the post commit static analyzer
and the llvm tests workflow both already use sccache.