COMP: ShapeUniqueLabelMapFilter test was missing.

The code for the ShapeUniqueLabelMapFilter test was in a cxx file,
but it was not being invoked from the CMakeLists.txt file. It was
rightfully reported as having zero code coverage.

Change-Id: I8ea7af073a171ec0f758e8530555a5f49926eff0
BUG: itkLoggerThreadWrapper test was disabled.

These changes restores the itkLoggerThreadWrapper test in the CMakeLists.txt
file, and adds to it a couple of calls to raise the code coverage of the class.

As a result of analyzing the logic, the operations type FLUSH was removed,
since there was no path to ever set it.

The error management logic of the pInfo data structure in the threaded function
was inverted, leaving the cases of null pointers to fall back in the default
return of the threaded function.

Change-Id: I876e10c280a8ca4569105c382f327ad601dd6e91
Merge topic 'itkLoggerThreadWrapper_CodeCoverage'

8cb14fa9 BUG: itkLoggerThreadWrapper test was disabled.
Merge topic 'tkShapeUniqueLabelMapFilter_Code_Coverage'

406e6d30 COMP: ShapeUniqueLabelMapFilter test was missing.