Clean up users of rust_dbg_call
`rust_dbg_call` is a C test helper that until this PR was declared in C with `void*` arguments and used in Rust _mostly_ with `libc::uintptr_t` arguments. Nearly every user just wants to pass integers around, so I've changed all users to `uint64_t` or `u64`.
The single test that actually used the pointer-ness of the argument is a test for ensuring that Rust can make extern calls outside of tasks. Rust hasn't had tasks for quite a few years now, so I'm deleting that test under the same logic as the test deleted in https://github.com/rust-lang/rust/pull/124073
6e172c5fde