Fix typo passing flags to rustc

Author: ecstatic-morse

src/test/ui/issues/issue-23477.rs

@@ -1,5 +1,5 @@
 // build-pass (FIXME(62277): could be check-pass?)
-// compiler-flags: -g
+// compile-flags: -g
 
 pub struct Dst {
     pub a: (),