Diagnostics should use container & JRE names

Previously the diagnostics when more than one container or more than
one JRE detected an application included the container or JRE detect
tags rather than the container or JREs themselves. This gave rise
to diagnostics such as:

Application can be run by more than one container: java-main,
tomcat-7.0.42, tomcat-buildpack-support-1.1.1

which was misleading since tomcat-buildpack-support-1.1.1 is not a
container.

Change the diagnostics to use containers and JREs. For example, the
above diagnostic then becomes:

[#57611752]