Fix Linear3D Indexing if Iteration Space Rank < 3

The Linear3D launch config setup did not pad its work_items lambda with ones if the iteration space rank was less than three. This MR fixes and tests this behavior.

changed milestone to %Release 2.0

added Bug label

requested review from @zy69guqi

assigned to @da15siwa

approved this merge request

mentioned in commit cd25546f

merged