feat: support wasm exit and signal exit

[Joinhack]

1. support the wasm exit code and signal exit like kill in unix.

[coveralls]

Pull Request Test Coverage Report for Build 12162112869

Details

• 8 of 13 (61.54%) changed or added relevant lines in 1 file are covered.
• 4 unchanged lines in 1 file lost coverage.
• Overall coverage decreased (-0.003%) to 15.444%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
blockless/src/lib.rs	8	13	61.54%

Files with Coverage Reduction	New Missed Lines	%
../../../.cargo/registry/src/index.crates.io-6f17d22bba15001f/tokio-1.42.0/src/runtime/task/raw.rs	4	61.29%

Totals
Change from base Build 12157494021:	-0.003%
Covered Lines:	5794
Relevant Lines:	11416

---

💛 - Coveralls