Add regression test

Author: oli-obk

src/test/ui/consts/match_ice.rs

@@ -1,11 +1,10 @@
-// compile-pass
 // https://github.com/rust-lang/rust/issues/53708
 
 struct S;
 
 fn main() {
     const C: &S = &S;
-    match C {
-        C => {}
+    match C { //~ ERROR non-exhaustive
+        C => {} // this is a common bug around constants and references in patterns
     }
 }

src/test/ui/consts/match_ice.stderr

@@ -0,0 +1,9 @@
+error[E0004]: non-exhaustive patterns: `&S` not covered
+  --> $DIR/match_ice.rs:7:11
+   |
+LL |     match C { //~ ERROR non-exhaustive
+   |           ^ pattern `&S` not covered
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0004`.