SystemTools: Drop optional FindProgramPath arguments

No call sites in CMake, ITK, ParaView, or VTK use these. Drop them to avoid using CMAKE_INTDIR.

requested review from @ben.boeckel

assigned to @brad.king

Do: stage

mentioned in issue cmake/cmake#24384

Do: merge

mentioned in commit 6444eb9a

merged

mentioned in merge request cmake/cmake!8175 (merged)