Add tests to verify closing task in event callback does not crash or error #1123

All 1 910 tests pass, 338 skipped in 43m 46s

34 files ± 0 34 suites ±0 43m 46s ⏱️ +4s
2 248 tests ± 0 1 910 ✅ ± 0 338 💤 + 2 0 ❌ - 2
39 690 runs - 28 34 134 ✅ - 28 5 556 💤 +20 0 ❌ - 20

Results for commit c29ef19. ± Comparison against earlier commit 19cb33b.