Test multiple variants

Co-Authored-By: Mazdak Farrokhzad <twingoow@gmail.com>

Author: jyn514

src/test/ui/consts/control-flow/single-arm-match-wild.rs

@@ -15,5 +15,7 @@ const fn f(e: E) -> usize {
 }
 
 fn main() {
+    const X: usize = f(E::C);
+    assert_eq!(X, 0);
     assert_eq!(f(E::A), 0);
 }