Bug 577552 - Switch tests to mockito

Convert equinox.region.tests.
Remove useless target file.
Do some slight modernization to have it less verbose as newer Java
versions allow.

Change-Id: Ifbf4f4b9b08c32c57a02a537656566b2ae231d15
Signed-off-by: Alexander Kurtakov <akurtako@redhat.com>
Reviewed-on: https://git.eclipse.org/r/c/equinox/rt.equinox.bundles/+/188391
Tested-by: Equinox Bot <equinox-bot@eclipse.org>
7 files changed