Remove direct Azul links

Their website is down.

source/posts/2019-05-21-official-stance-on-java.html.markdown.erb

@@ -33,12 +33,11 @@ For more information about this, take a look at:
 
 As an alternative to purchasing commercial support from Oracle, organisations may want to consider [OpenJDK](https://openjdk.org/), the free, open-source implementation of Java SE. The OpenJDK project will follow Oracle’s 6 month release cadence for Java, and will publish patches and security updates. There are commercially supported and open-source distributions of OpenJDK that GoCD users may possibly use:
 
-- [Zulu](https://www.azul.com/downloads/zulu/) from Azul Systems
-- [Corretto](https://aws.amazon.com/corretto/) from Amazon
-- RedHat’s [OpenJDK](https://developers.redhat.com/products/openjdk/overview/)
+- [Azul Zulu](https://whichjdk.com/#azul-zulu) from Azul Systems
+- [Corretto](https://whichjdk.com/#amazon-corretto) from Amazon
 - [AdoptOpenJDK](https://adoptopenjdk.net/)
 
-A comparison of the different JDK offerings, by Azul (creators of Zulu JDK) is [available here](https://www.azul.com/products/zulu-enterprise/jdk-comparison-matrix-2/). The GoCD team builds and tests all releases against an appropriate distribution of OpenJDK.
+A comparison of the different JDK offerings is [available here](https://whichjdk.com/). The GoCD team builds and tests all releases against an appropriate distribution of OpenJDK.
 
 ## What does this mean for users of GoCD?