Test `u8::is_ascii` alongside `char::is_ascii`

src/test/ui/consts/is_ascii.rs

@@ -3,7 +3,13 @@
 static X: bool = 'a'.is_ascii();
 static Y: bool = 'ä'.is_ascii();
 
+static BX: bool = b'a'.is_ascii();
+static BY: bool = 192u8.is_ascii();
+
 fn main() {
     assert!(X);
     assert!(!Y);
+
+    assert!(BX);
+    assert!(!BY);
 }