COMP: Initialized derivs array to zero.
COMP: Initialized derivs array to zero.

This resolves the following uninitialized compiler warning for the HexahedronCell:

/localscratch/Users/kjweimer/ITK/Modules/Core/Common/include/itkHexahedronCell.hxx:385:34: warning: ‘derivs[16]’ is used uninitialized in this function [-Wuninitialized]
  385 |         tcol[j] += pt[j] * derivs[i + 2 * Self::NumberOfPoints];
      |                                  ^

hjmjohnson/ITK,Kitware/ITK,Kitware/ITK,thewtex/ITK,BRAINSia/ITK,hjmjohnson/ITK,richardbeare/ITK,hjmjohnson/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,Kitware/ITK,BRAINSia/ITK,Kitware/ITK,hjmjohnson/ITK,hjmjohnson/ITK,hjmjohnson/ITK,thewtex/ITK,hjmjohnson/ITK,BRAINSia/ITK,InsightSoftwareConsortium/ITK,richardbeare/ITK,richardbeare/ITK,thewtex/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,BRAINSia/ITK,BRAINSia/ITK,richardbeare/ITK,thewtex/ITK,Kitware/ITK,BRAINSia/ITK,richardbeare/ITK,BRAINSia/ITK,richardbeare/ITK,InsightSoftwareConsortium/ITK,InsightSoftwareConsortium/ITK,richardbeare/ITK,thewtex/ITK,Kitware/ITK,thewtex/ITK,thewtex/ITK,Kitware/ITK