ci(fedora41): move Perforce download to a separate image

It improves parallelization and speeds up the build.
Since downloading is a quick task, put the results to the final image
at the beginning to avoid waiting for other (longer) tasks.

.gitlab/ci/docker/fedora41/Dockerfile

@@ -49,11 +49,20 @@ RUN --mount=type=bind,source=dnf.conf,target=/etc/dnf/dnf.conf \
     sh /root/install_iwyu.sh
 
 
+FROM ${BASE_IMAGE} AS p4-dl
+# Download Perforce.
+# NOTE `curl` is pre-installed in the base image.
+RUN curl -C- -L https://www.perforce.com/downloads/perforce/r21.2/bin.linux26x86_64/helix-core-server.tgz \
+  | tar -C /usr/local/bin -xvzf - -- p4 p4d
+
+
 FROM ${BASE_IMAGE}
 LABEL maintainer="Ben Boeckel <ben.boeckel@kitware.com>"
 
 ENV RBENV_ROOT=/opt/rbenv
 
+COPY --from=p4-dl --chown=root:root /usr/local/bin/p4 /usr/local/bin/p4d /usr/local/bin
+
 RUN --mount=type=bind,source=dnf.conf,target=/etc/dnf/dnf.conf \
     --mount=type=bind,source=install_deps.sh,target=/root/install_deps.sh \
     --mount=type=bind,source=deps_packages.lst,target=/root/deps_packages.lst \

.gitlab/ci/docker/fedora41/install_deps.sh

@@ -15,7 +15,3 @@ find /usr/lib64/python3.13/site-packages/breezy -type d -a -name tests -exec rm
 # Ruby rbenv
 rbenv install 3.1.2
 rbenv global 3.1.2
-
-# Perforce
-curl -L https://www.perforce.com/downloads/perforce/r21.2/bin.linux26x86_64/helix-core-server.tgz -o - \
-  | tar -C /usr/local/bin -xvzf - -- p4 p4d