Remove unneeded javaVersion override (#2622)

* Remove unneeded javaVersion override

We have tinybundles-4, hence there is no need to compile for Java 8.

Signed-off-by: Robert Varga <robert.varga@pantheon.tech>

* Symlink main's test jre.properties

The file used for testing is quite stale, this turns it into a symlink
to production version -- thus making sure it is always up-to-date.

Signed-off-by: Robert Varga <robert.varga@pantheon.tech>

---------

Signed-off-by: Robert Varga <robert.varga@pantheon.tech>

Author: rovarga

main/pom.xml

@@ -36,8 +36,6 @@
 
     <properties>
         <appendedResourcesDirectory>${basedir}/../etc/appended-resources</appendedResourcesDirectory>
-        <!-- it can be removed after the tinybundle 4 update -->
-        <javaVersion>8</javaVersion>
     </properties>
 
     <dependencyManagement>