[CI] Add "Nightly" releases support for manual runs of sycl-linux-run-tests.yml (#19690)

We also have "official" releases like "v6.1.0" but they have different
archive name format *and* lack necessary tools for running E2E tests
(like `FileCheck`, etc.). As such, limit support for "Nightly" releases
format.

Author: aelovikov-intel

.github/workflows/sycl-linux-run-tests.yml

@@ -179,6 +179,10 @@ on:
           - e2e
           - cts
           - benchmarks
+      toolchain_release_tag:
+        description: |
+          Tag of a "Nightly" release at https://github.com/intel/llvm/releases.
+        default: ''
 
       env:
         description: |
@@ -256,11 +260,6 @@ jobs:
       uses: actions/download-artifact@v4
       with:
         name: ${{ inputs.toolchain_artifact }}
-    - name: Debug prints [workflow_run]
-      if: inputs.toolchain_artifact != '' && github.event_name == 'workflow_run'
-      run: |
-        pwd
-        ls
     - name: Download SYCL toolchain [workflow_run]
       # NOTE: This is for `sycl-linux-precommit-aws.yml`.
       if: inputs.toolchain_artifact != '' && github.event_name == 'workflow_run'
@@ -299,6 +298,17 @@ jobs:
         rm -f ${{ inputs.toolchain_artifact_filename }}
         echo PATH=$PWD/toolchain/bin/:$PATH >> $GITHUB_ENV
         echo LD_LIBRARY_PATH=$PWD/toolchain/lib/:$LD_LIBRARY_PATH >> $GITHUB_ENV
+    - name: Download SYCL toolchain using release tag
+      if: inputs.toolchain_release_tag != ''
+      env:
+        TAG: ${{ inputs.toolchain_release_tag }}
+      shell: bash
+      run: |
+        mkdir toolchain
+        wget "https://github.com/intel/llvm/releases/download/$TAG/sycl_linux.tar.gz"
+        tar xf sycl_linux.tar.gz -C toolchain
+        echo PATH=$PWD/toolchain/bin/:$PATH >> $GITHUB_ENV
+        echo LD_LIBRARY_PATH=$PWD/toolchain/lib/:$LD_LIBRARY_PATH >> $GITHUB_ENV
     - run: which clang++ sycl-ls
     - run: sycl-ls --verbose
     - run: SYCL_UR_TRACE=1 sycl-ls