Remove redundant platform detection in test

test/sys/test_ptrace.rs

@@ -123,17 +123,6 @@ fn test_ptrace_syscall() {
 
     let _m = ::FORK_MTX.lock().expect("Mutex got poisoned by another test");
 
-    // FIXME: qemu-user doesn't implement ptrace on all architectures
-    // and retunrs ENOSYS in this case.
-    // We (ab)use this behavior to detect the affected platforms
-    // and skip the test then.
-    // On valid platforms the ptrace call should return Errno::EPERM, this
-    // is already tested by `test_ptrace`.
-    let err = ptrace::attach(getpid()).unwrap_err();
-    if err == Error::Sys(Errno::ENOSYS) {
-        return;
-    }
-
     match fork().expect("Error: Fork Failed") {
         Child => {
             ptrace::traceme().unwrap();