[tests] Remove XFail on pass.brat

It doesn't import from lib.kernel anymore, isn't victim to #13

brat/test/Test/Compile/Hugr.hs

@@ -25,7 +25,7 @@ outputDir = prefix </> "output"
 
 -- examples that we expect to compile, but then to fail validation
 invalidExamples :: [FilePath]
-invalidExamples = map ((++ ".brat") . ("examples" </>)) ["pass", "thunks"]
+invalidExamples = map ((++ ".brat") . ("examples" </>)) ["thunks"]
 
 -- examples that we expect not to compile
 -- Note this includes those with remaining holes; it would be better