github: tune ext4 for speed and reclaim some space

ceph's mon was complaining about low free space in the
rootfs.

Signed-off-by: Simon Deziel <simon.deziel@canonical.com>

.github/workflows/tests.yml

@@ -20,6 +20,27 @@ jobs:
     name: Code tests
     runs-on: ubuntu-22.04
     steps:
+      - name: Tune ext4 for performance
+        run: |
+          set -eux
+          # optimize ext4 FSes for performance, not reliability
+          for fs in $(findmnt --noheading --type ext4 --list --uniq | awk '{print $1}'); do
+            # nombcache and data=writeback cannot be changed on remount
+            sudo mount -o remount,noatime,barrier=0,commit=6000 "${fs}"
+          done
+
+      - name: Reclaim some space
+        run: |
+          set -eux
+          df -h /
+          # dotnet
+          sudo rm -rf /usr/share/dotnet
+          # android
+          sudo rm -rf /usr/local/lib/android
+          # haskell
+          sudo rm -rf /opt/ghc
+          df -h /
+
       - name: Checkout
         uses: actions/checkout@v4