CI: add workaround for nested composite actions issue

Because of https://github.com/actions/runner/issues/2009 the deeply
nested action cache was failing to save the cache in the post run phase.

For the moment we just avoid the nesting with a copy-pasted action
snippet.

.github/actions/cache-query-compilation/action.yml

@@ -14,11 +14,35 @@ outputs:
 runs:
   using: composite
   steps:
-    - name: Cache the query compilation caches
-      uses: ./.github/actions/incremental-cache
+    # calculate the merge-base with main, in a way that works both on PRs and pushes to main.
+    - name: Calculate merge-base
+      shell: bash
+      if: ${{ github.event_name == 'pull_request' }}
+      env:
+        BASE_BRANCH: ${{ github.base_ref }}
+      run: |
+        MERGE_BASE=$(git cat-file commit $GITHUB_SHA | grep '^parent ' | head -1 | cut -f 2 -d " ")
+        echo "merge_base=$MERGE_BASE" >> $GITHUB_ENV
+    - name: Restore read-only cache (PR)
+      if: ${{ github.event_name == 'pull_request' }}
+      uses: erik-krogh/actions-cache@a88d0603fe5fb5606db9f002dfcadeb32b5f84c6
       with:
         path: '**/.cache'
-        key: codeql-compile-${{ inputs.key }}
+        read-only: true
+        key: ${{ inputs.key }}-pr-${{ github.sha }}
+        restore-keys: |
+          ${{ inputs.key }}-${{ github.base_ref }}-${{ env.merge_base }}
+          ${{ inputs.key }}-${{ github.base_ref }}-
+          ${{ inputs.key }}-main-
+    - name: Fill cache (push)
+      if: ${{ github.event_name != 'pull_request' }}
+      uses: erik-krogh/actions-cache@a88d0603fe5fb5606db9f002dfcadeb32b5f84c6
+      with:
+        path: '**/.cache'
+        key: ${{ inputs.key }}-${{ github.ref_name }}-${{ github.sha }} # just fill on main
+        restore-keys: | # restore the latest cache if the exact cache is unavailable, to speed up compilation.
+          ${{ inputs.key }}-${{ github.ref_name }}-
+          ${{ inputs.key }}-main-
     - name: Fill compilation cache directory
       id: fill-compilation-dir
       shell: bash

.github/actions/incremental-cache/action.yml

@@ -1,44 +0,0 @@
-name: Setup an incremental cache
-description: Special cache wrapper to be run on pull requests and pushes, that will try to restore
-  a cache as close as possible to the merge base
-
-inputs:
-  path:
-    description: 'The path to cache'
-    required: true
-  key:
-    description: 'The cache key to use - should be unique to the workflow'
-    required: true
-
-runs:
-  using: composite
-  steps:
-    # calculate the merge-base with main, in a way that works both on PRs and pushes to main.
-    - name: Calculate merge-base
-      shell: bash
-      if: ${{ github.event_name == 'pull_request' }}
-      env:
-        BASE_BRANCH: ${{ github.base_ref }}
-      run: |
-        MERGE_BASE=$(git cat-file commit $GITHUB_SHA | grep '^parent ' | head -1 | cut -f 2 -d " ")
-        echo "merge_base=$MERGE_BASE" >> $GITHUB_ENV
-    - name: Restore read-only cache (PR)
-      if: ${{ github.event_name == 'pull_request' }}
-      uses: erik-krogh/actions-cache@a88d0603fe5fb5606db9f002dfcadeb32b5f84c6
-      with:
-        path: ${{ inputs.path }}
-        read-only: true
-        key: ${{ inputs.key }}-pr-${{ github.sha }}
-        restore-keys: |
-          ${{ inputs.key }}-${{ github.base_ref }}-${{ env.merge_base }}
-          ${{ inputs.key }}-${{ github.base_ref }}-
-          ${{ inputs.key }}-main-
-    - name: Fill cache (push)
-      if: ${{ github.event_name != 'pull_request' }}
-      uses: erik-krogh/actions-cache@a88d0603fe5fb5606db9f002dfcadeb32b5f84c6
-      with:
-        path: ${{ inputs.path }}
-        key: ${{ inputs.key }}-${{ github.ref_name }}-${{ github.sha }} # just fill on main
-        restore-keys: | # restore the latest cache if the exact cache is unavailable, to speed up compilation.
-          ${{ inputs.key }}-${{ github.ref_name }}-
-          ${{ inputs.key }}-main-