[CI] Remove ccache from Linux CI Container

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.

Pull Request: llvm#149197

Author: boomanaiden154

.github/workflows/containers/github-action-ci/Dockerfile

@@ -58,10 +58,8 @@ RUN apt-get update && \
     python3-psutil \
     sudo \
     # These are needed by the premerge pipeline. Pip is used to install
-    # dependent python packages and ccache is used for build caching. File and
-    # tzdata are used for tests.
+    # dependent python packages. File and tzdata are used for tests.
     python3-pip \
-    ccache \
     file \
     tzdata && \
     apt-get clean && \