Use ptr::cast instead of as casts in several places. (#3507)

`ptr::cast` has the advantage of being unable to silently cast
`*const T` to `*mut T`. This turned up several places that were
performing such casts, which this PR also fixes.

crates/jit/src/profiling/vtune_linux.rs

@@ -130,7 +130,7 @@ impl State {
             .unwrap_or_else(|| format!("wasm_module_{}", global_module_id));
 
         for (idx, func) in module.finished_functions() {
-            let (addr, len) = unsafe { ((*func).as_ptr() as *const u8, (*func).len()) };
+            let (addr, len) = unsafe { ((*func).as_ptr().cast::<u8>(), (*func).len()) };
             let method_name = super::debug_name(module.module(), idx);
             let method_id = self.get_method_id();
             log::trace!(