Use an outlandish target feature for the negative case

Author: cuviper

tests/ui/sse2.rs

@@ -19,7 +19,7 @@ fn main() {
         assert!(cfg!(target_feature = "sse2"),
                 "SSE2 was not detected as available on an x86 platform");
     }
-    // check a negative case too -- allowed on x86, but not enabled by default
-    assert!(cfg!(not(target_feature = "avx512f")),
-            "AVX512 shouldn't be detected as available by default on any platform");
+    // check a negative case too -- certainly not enabled by default
+    assert!(cfg!(not(target_feature = "ferris_wheel")),
+            "🎡 shouldn't be detected as available by default on any platform");
 }