[hls-graph] clean up databaseDirtySet (#2294)

* attempt to fix hiedb lock errors

it looks like the test runner has a preexisting process locking the hiedb

* Move ghcide cache to the tmp folder

* Use ${{ runner.temp }}

* clean up the hie-bios cache too

* The runner context doesn't exist outside the steps section

.github/workflows/test.yml

@@ -138,6 +138,15 @@ jobs:
           sed -i.bak -e 's/Paths_haskell_language_server/Paths_hls/g' \
                      src/**/*.hs exe/*.hs
 
+      # this is only safe if the test environment is isolated
+      - name: setup ide cache
+        run: |
+          export XDG_CACHE_HOME=$RUNNER_TEMP/cache
+          rm -rf ~/.cache/ghcide
+          rm -rf ~/.cache/hie-bios
+          rm -rf $XDG_CACHE_HOME/ghcide
+          rm -rf $XDG_CACHE_HOME/hie-bios
+
       - if: ${{ needs.pre_job.outputs.should_skip != 'true' }}
         name: Build
         # Retry it three times to workaround compiler segfaults in windows