it0026: verify that native-lib-loader works also with .jar files

So far, we only tested whether the NarSystem generated in the presence
of the native-lib-loader dependency worked with *unpacked* classes.
However, the whole point of the exercise was to support bundled classes
and bundled native libraries.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Rename it0026 to reflect the name of native-lib-loader precisely

The dependency we are special-casing is called native-lib-loader, not
native-library-loader. Let's avoid confusion and use the correct name
consistently.

This issue was noticed when this developer was puzzled why

	mvn -Dinvoker.test=it0026-native-lib-loader

would not Do The Right Thing ;-)

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>