Temporarily disable TSAN

Author: colesbury

.github/workflows/build.yml

@@ -496,7 +496,7 @@ jobs:
   build_tsan_free_threading:
     name: 'Thread sanitizer (free-threading)'
     needs: check_source
-    if: needs.check_source.outputs.run_tests == 'true'
+    if: needs.check_source.outputs.run_tests == 'true' && false
     uses: ./.github/workflows/reusable-tsan.yml
     with:
       config_hash: ${{ needs.check_source.outputs.config_hash }}