STYLE: Apply kwstyle to Modules/Filtering tests

KWStyle was not checking tests. However, the git hook for KWStyle did
check tests if they were modified. This topic cleans itk tests and
reduces developer frustration when committing changes to test.

Change-Id: If11cf8a06677654a2f44dbd331b55ca0ee410533
Merge topic 'StyleForFilteringTests'

9c2f256 STYLE: Apply kwstyle to Modules/Filtering tests