For feature-based launches the included features/plug-ins are ignored if
the including element specifies an environment that does not match the
environment specified by the current target-platform (or as fall-back by
the running-platform).

The environment specified for a feature itself is considered in the same
way, for included and required features.

Change-Id: Iad73bb68e8ccc92a7e611e7898b60519eee5239b
Signed-off-by: Hannes Wellmann <wellmann.hannes1@gmx.net>
Reviewed-on: https://git.eclipse.org/r/c/pde/eclipse.pde.ui/+/186948
Tested-by: PDE Bot <pde-bot@eclipse.org>