fix test

Author: MarinPostma

tests/disas/winch/x64/atomic/rmw/i64_atomic_rmw32_subu.wat

@@ -4,7 +4,7 @@
 (module
   (memory 1 1 shared)
   (func (export "_start") (result i64)
-        (i64.atomic.rmw8.sub_u (i32.const 0) (i64.const 42))))
+        (i64.atomic.rmw32.sub_u (i32.const 0) (i64.const 42))))
 ;; wasm[0]::function[0]:
 ;;       pushq   %rbp
 ;;       movq    %rsp, %rbp