Move tests that do not compile to XFAIL

Author: lucic71

tests/lit/lit/formats/Cpp2RustTest.py

@@ -163,7 +163,7 @@ def fail(str, code = fail_code):
     if should_not_compile:
       if returncode != 0:
         shutil.rmtree(tmp_dir, True)
-        return lit.Test.PASS, ''
+        return lit.Test.XFAIL, ''
       return fail('expected no-compile but compiled successfully')
     if returncode != 0:
       return fail('cargo failed\n' + err)