Avoid should-fail in a codegen-llvm test

tests/codegen-llvm/option-niche-unfixed/option-nonzero-eq.rs

@@ -1,6 +1,5 @@
-//@ should-fail
+//@ known-bug: #49892
 //@ compile-flags: -Copt-level=3 -Zmerge-functions=disabled
-//! FIXME(#49892)
 //! Test that the derived implementation of `PartialEq` for `Option` is not fully
 //! optimized by LLVM. If this starts passing, the test and manual impl should
 //! be removed.
@@ -18,7 +17,7 @@ pub enum Option<T> {
 #[no_mangle]
 pub fn non_zero_eq(l: Option<NonZero<u32>>, r: Option<NonZero<u32>>) -> bool {
     // CHECK: start:
-    // CHECK-NEXT: icmp eq i32
-    // CHECK-NEXT: ret i1
+    // COMMENTEDCHECK-NEXT: icmp eq i32
+    // COMMENTEDCHECK-NEXT: ret i1
     l == r
 }