Revert "test: fix flaky test_env_arg_ignore_signal_valid_signals timing issue"

This reverts commit 31069b9.

Author: naoNao89

tests/by-util/test_env.rs

@@ -48,14 +48,7 @@ impl Target {
             .spawn()
             .expect("failed to send signal")
             .wait();
-        // Give the process time to handle the signal and exit
-        // Use a longer delay with retries to handle slower systems
-        for _ in 0..50 {
-            self.child.delay(10);
-            if !self.child.is_alive() {
-                break;
-            }
-        }
+        self.child.delay(100);
     }
     fn is_alive(&mut self) -> bool {
         self.child.is_alive()