The fix for JDK-8067883 remove the last use of a variable holding a diagnostic, the variable can now be removed:

https://github.com/openjdk/jdk/commit/75b2a03bf9e4e83fde574f2181cd08a2cd6eaffe#diff-c7b5b2fe0339273ba04db73761f98884a30541ca66ac0af775b10f7a37223be0R2546-R2548