Support running Beanshell's bsh.Interpreter class

When debugging why certain Java code behaves unexpectedly, I often turn to [Beanshell](http://beanshell.org/) or [Beanshell2](https://code.google.com/p/beanshell2/). However, Avian VM could not run either out of the box.

This topic branch fixes the issues I encountered when running Beanshell (and only those) with the most critical fix being the one for getClass().getComponentType(): the component type of, say, ```Class[][]``` was reported as ```Class``` instead of the correct ```Class[]```.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>