* Introduce common `bzero` libc implementation.

* Update test name according to review

Co-authored-by: Linus Groh <mail@linusgroh.de>

* address code review

- import common implementation when musl or wasi is included
- don't use `c_builtins`, use `@memset`

* bzero calling conv to .c

* Apply review

Co-authored-by: Veikka Tuominen <git@vexu.eu>

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Co-authored-by: Linus Groh <mail@linusgroh.de>
Co-authored-by: Veikka Tuominen <git@vexu.eu>