fix: remove non-zero check before __visit

[HerrCai0907]

In the implementation of __visit, we will do non-zero check, so in visitMemberOf, we don't need to emit non-zero check.
Emit them both maybe have some performance benefit (I don't do bench for it), but at least for -Oz target, we should remove it.

export function __visit(ptr: usize, cookie: i32): void {
  if (!ptr) return;
...

[CountBleck]

Looks great! How'd you notice this?

[HerrCai0907]

I am improving the runtime performance and reviewing generated code line by line. 😅