set thread context classloader in junit test vm

Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>
renamed 'Maven IT' to 'Maven JUnit Test'

This launch configuration type is expected to work both for unit
and integration tests. 'JUnit Test' better reflects the fact and
will likely be easier for users to understand.

Signed-off-by: Igor Fedorenko <igor@ifedorenko.com>