Fix Miri action

.github/workflows/check.yml

@@ -161,8 +161,16 @@ jobs:
         run: rustup component add rust-src miri
       - name: Run tests with sanitizer
         run: RUSTFLAGS="-Z sanitizer=${{ matrix.sanitizer }} -Z sanitizer-memory-track-origins" cargo test -Z build-std --target $TARGET --no-default-features --features "cli web-app real-world-infra test-fixture descriptive-gate ${{ matrix.features }}"
-      - name: Run seq_join tests with Miri
-        run: cargo test --target $TARGET --lib seq_join --features "multi-threading"
+
+  miri:
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@v3
+    - uses: dtolnay/rust-toolchain@nightly
+    - name: Add Miri
+      run: rustup component add miri
+    - name: Run seq_join tests with Miri
+      run: cargo miri test --target $TARGET --lib seq_join --features "multi-threading"
 
   coverage:
     name: Measure coverage