Remove unrelated changes.

Author: xingxue-ibm

tests/ui/runtime/signal-alternate-stack-cleanup.rs

@@ -29,10 +29,7 @@ fn main() {
         // Install signal handler that runs on alternate signal stack.
         let mut action: sigaction = std::mem::zeroed();
         action.sa_flags = (SA_ONSTACK | SA_SIGINFO) as _;
-        #[cfg(not(target_os = "aix"))]
-        { action.sa_sigaction = signal_handler as sighandler_t}
-        #[cfg(target_os = "aix")]
-        { action.sa_union.__su_sigaction = signal_handler as sighandler_t }
+        action.sa_sigaction = signal_handler as sighandler_t;
         sigaction(SIGWINCH, &action, std::ptr::null_mut());
 
         // Send SIGWINCH on exit.