runtime: cleanup legacy tests of alt multi-threaded runtime (#7451)

Signed-off-by: ADD-SP <[email protected]>

.github/workflows/loom.yml

@@ -95,28 +95,3 @@ jobs:
         working-directory: tokio
         env:
           SCOPE: ${{ matrix.scope }}
-
-  loom-multi-thread-alt:
-    name: loom ALT multi-thread scheduler
-    # base_ref is null when it's not a pull request
-    if: github.repository_owner == 'tokio-rs' && (contains(github.event.pull_request.labels.*.name, 'R-loom-multi-thread-alt') || (github.base_ref == null))
-    runs-on: ubuntu-latest
-    strategy:
-      matrix:
-        include:
-          - scope: loom_multi_thread_alt::group_a
-          - scope: loom_multi_thread_alt::group_b
-          - scope: loom_multi_thread_alt::group_c
-          - scope: loom_multi_thread_alt::group_d
-    steps:
-      - uses: actions/checkout@v4
-      - name: Install Rust ${{ env.rust_stable }}
-        uses: dtolnay/rust-toolchain@master
-        with:
-            toolchain: ${{ env.rust_stable }}
-      - uses: Swatinem/rust-cache@v2
-      - name: loom ${{ matrix.scope }}
-        run: cargo test --lib --release --features full -- --nocapture $SCOPE
-        working-directory: tokio
-        env:
-          SCOPE: ${{ matrix.scope }}