Program.Clone deep-copied the SubPrograms dictionary but left every
SubProgramCall pointing at the source's sub-program, and
SubProgramCall.Clone went through the Rotation setter, which re-rotated
that shared program to the call's stale angle. Copying a program with
hole lead-ins therefore rotated the source's holes, and rotating the
copy rotated the source again.
Program.Rotate also rotated a shared sub-program once per call, so two
identical holes (one deduplicated sub-program) turned twice.
Clone now binds calls to one private copy per shared sub-program
without re-aligning it, and Rotate turns each distinct sub-program once.
