Execution environments with no matching JREs should not show up in runtime wizard

In a new server / runtime wizard, execution environments such as java8 may show up in the list despite hte workspace having no java8 or higher JREs available. When the user selects the Java8 exec-env, an error is shown and the user cannot continue.

This execution environment should not appear in the list unless the user has a compatible JRE in the workspace.