index_experimental flag to enable index usages

Currently indexes are the bulk of the problem with `UPDATE` and
`DELETE`, while we work on fixing those it makes sense to disable
indexing since they are not stable. We want to try to make everything
else stable before we continue with indexing.

.github/workflows/rust.yml

@@ -93,7 +93,10 @@ jobs:
       - name: Test
         run: make test
         timeout-minutes: 20
-
+      - uses: "./.github/shared/install_sqlite"
+      - name: Test with index enabled
+        run: SQLITE_EXEC="scripts/limbo-sqlite3-index-experimental" make test
+        timeout-minutes: 20
   test-sqlite:
     runs-on: blacksmith-4vcpu-ubuntu-2404
     steps: