RFR: JDK-8204922: Create bootcycle jib profiles

[Erik Joelsson]

In order to test bootcycle builds more easily at Oracle, we need 
specific jib profiles for them. This patch adds that. I also make the 
linux-aarch64 profile explicitly build the aarch64 port instead of the 
arm64 port as well as disable warnings-as-errors since we currently have 
the readdir warning in that configuration.

Bug: https://bugs.openjdk.java.net/browse/JDK-8204922

Webrev: http://cr.openjdk.java.net/~erikj/8204093/webrev.01/

/Erik