RFR: JDK-8220530: Build compare script does not compare the contents of the test image

[Erik Joelsson]

This patch adds comparison of the test image, if present in both build 
output directories. I also cleaned away comparing of some old Oracle 
closed images that no longer exist.

Bug: https://bugs.openjdk.java.net/browse/JDK-8220530 
<https://bugs.openjdk.java.net/browse/JDK-8220530?filter=-1>

Webrev: http://cr.openjdk.java.net/~erikj/8220530/webrev.01/index.html

/Erik