Fix feature-test failing with surefire 2.18

feature-test fails maven-surefire-plugin 2.18 (but works with 2.17) due
to it assumming the constructor is called only once and modifying global
state. That global state is guarded from multiple modifications with an
Error. Move the offending initialization into static initializer, thus
ensuring we invoke the function only once.

Change-Id: I771ce384927769436ff0c8133471cefe27954a3d
Signed-off-by: Robert Varga <rovarga@cisco.com>