chore(ci): teardown build instance only if setup has run

In case of a re-run attempt, if one asks for only failing jobs to
be re-run (e.g. MacOS job on GitHub hosted runner) and the
previous attempt was successful regarding setup-build-teardown,
then we would try to teardown again an instance already gone.
This would cause an error in the CI.

By checking the 'github.run_attempt' number, we ensure that we run
the teardown only if the setup has occurred during the same run
attempt.

.github/workflows/cargo_build_common.yml

@@ -72,6 +72,7 @@ jobs:
     runs-on: ubuntu-latest
     outputs:
       runner-name: ${{ steps.start-remote-instance.outputs.label || steps.start-github-instance.outputs.runner_group }}
+      run_attempt: ${{ github.run_attempt }} # On a re-run with a successful previous run for this job, the run_attempt will not be incremented
     steps:
       - name: Start remote instance
         id: start-remote-instance
@@ -211,7 +212,9 @@ jobs:
 
   teardown-instance:
     name: cargo_build_common/teardown-instance
-    if: ${{ always() && needs.setup-instance.result == 'success' }}
+    if: ${{ always() &&
+      needs.setup-instance.result == 'success' &&
+      github.run_attempt == needs.setup-instance.outputs.run_attempt }} # Only run if setup-instance has been executed during this run attempt
     needs: [setup-instance, builds]
     runs-on: ubuntu-latest
     steps: