MiniMaven: be careful with classifiers

Just because we parsed a .pom file does not mean that we have
the correct classifier, since we reuse MavenProject instances for
dependencies.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
MiniMaven: special-case imglib{,2}-tests

It's a test-only project... nothing to see here, please move along.

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