The second part of issue https://bugs.openjdk.java.net/browse/JDK-8263668 to update the code in the `java.time` package to make use of the `instanceof` pattern variable.

As the original PR spanned a large number of files, it was decided to split these changes across two separate issues.


See https://openjdk.java.net/jeps/394 for further information on Pattern Matching for instanceof