panic ui test: Add a test for panic::always_abort

Our existing tests are only on Unix.  We want a general one too.

Signed-off-by: Ian Jackson <ijackson@chiark.greenend.org.uk>

src/test/ui/panics/abort-on-panic.rs

@@ -43,10 +43,17 @@ fn testrust() {
     should_have_aborted();
 }
 
+fn test_always_abort() {
+    panic::always_abort();
+    let _ = panic::catch_unwind(|| { panic!(); });
+    should_have_aborted();
+}
+
 fn main() {
     let tests: &[(_, fn())] = &[
         ("test", test),
         ("testrust", testrust),
+        ("test_always_abort", test_always_abort),
     ];
 
     let args: Vec<String> = env::args().collect();