CI: Reclaim space after package operations

Rather than reclaiming space before updating the packages do
it afterwards.  This avoids issues with apt returning an
error due to missing files on the system.

This commit includes a revert for 6320b9e6.

Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #14387

.github/workflows/scripts/reclaim_disk_space.sh

@@ -1,19 +1,20 @@
-#!/bin/sh -x
+#!/bin/sh
 
 set -eu
 
 # remove 4GiB of images
 sudo systemd-run docker system prune --force --all --volumes
 
-# remove unused packages
-sudo apt remove -q --purge firefox
-
 # remove unused software
 sudo systemd-run rm -rf \
   "$AGENT_TOOLSDIRECTORY" \
   /opt/* \
   /usr/local/* \
   /usr/share/az* \
+  /usr/share/dotnet \
   /usr/share/gradle* \
   /usr/share/miniconda \
-  /usr/share/swift
+  /usr/share/swift \
+  /var/lib/gems \
+  /var/lib/mysql \
+  /var/lib/snapd