ci: reproduce leak with parallel cmd tests

Author: happy-v587

.github/workflows/ci.yml

@@ -352,7 +352,7 @@ jobs:
             # report is emitted by the cmd test binary. Keep this diagnostic
             # invocation focused so symbolized LSan feedback is fast.
             cargo +${SANITIZER_TOOLCHAIN} test -Z build-std --target x86_64-unknown-linux-gnu \
-              -p cmd --lib -- --test-threads=1 2>&1 | tee sanitizer.log
+              -p cmd --lib 2>&1 | tee sanitizer.log
           elif [[ "${{ matrix.sanitizer }}" == "thread" ]]; then
             # RocksDB/libstdc++ trigger sanitizer reports and timing instability
             # in storage integration test binaries. The net crate's end-to-end