[CI][SYCL] Checkout proper revision of the repo for llvm-test-suite run (#8835)

Author: aelovikov-intel

.github/workflows/sycl_linux_build_and_test.yml

@@ -220,6 +220,7 @@ jobs:
       with:
         persist-credentials: false
         path: llvm
+        ref: ${{ inputs.build_ref || github.ref }}
     # TODO should this action be packed into container as well?
     - uses: ./llvm/devops/actions/llvm_test_suite
       name: Run LLVM Test Suite