Bug fix: do not run tests twice on java8

Currently, on java8, tests are sometimes executed twice, probably because HavaRunner relies on bug on Java7.

See http://mail.openjdk.java.net/pipermail/jdk8-dev/2014-January/003955.html and https://bugs.openjdk.java.net/browse/JDK-6695379

Running only non-bridge test methods fixes the issue.

Also upgraded Scala to 2.11 series to make it possible to run on java8, and actually verify this bug.