Turbopack: run tests with multiple threads (#84074)
These tests were broken
```
➜ next.js-other git:(mischnic/parallelize-merged-module-info) UPDATE=1 cargo nextest run -p turbopack-tests -E 'test(test_tests__execution__turbopack__basic__esm_this__input__index_js)' --no-capture
Finished `test` profile [unoptimized + debuginfo] target(s) in 0.37s
────────────
Nextest run ID 1a4f74a3-a8a3-4049-bd6d-aa55a30c6dc2 with nextest profile: default
Starting 1 test across 3 binaries (247 tests skipped)
START turbopack-tests::execution test_tests__execution__turbopack__basic__esm_this__input__index_js
running 1 test
Input: turbopack/crates/turbopack-tests/tests/execution/turbopack/basic/esm-this/input/index.js
thread 'test_tests__execution__turbopack__basic__esm_this__input__index_js' panicked at turbopack/crates/turbo-tasks/src/scope.rs:166:5:
can call blocking only when running on the multi-threaded runtime
note: run with `RUST_BACKTRACE=1` environment variable to display a backtrace
thread 'test_tests__execution__turbopack__basic__esm_this__input__index_js' panicked at turbopack/crates/turbopack-tests/tests/execution.rs:99:77:
called `Result::unwrap()` on an `Err` value: channel closed
test test_tests__execution__turbopack__basic__esm_this__input__index_js ... FAILED
failures:
failures:
test_tests__execution__turbopack__basic__esm_this__input__index_js
test result: FAILED. 0 passed; 1 failed; 0 ignored; 0 measured; 169 filtered out; finished in 0.18s
FAIL [ 0.195s] turbopack-tests::execution test_tests__execution__turbopack__basic__esm_this__input__index_js
Cancelling due to test failure:
────────────
Summary [ 0.195s] 1 test run: 0 passed, 1 failed, 247 skipped
FAIL [ 0.195s] turbopack-tests::execution test_tests__execution__turbopack__basic__esm_this__input__index_js
error: test run failed
```
