Do an agent-assisted audit of huge array support

We have been fixing quite a few huge-array issues recently. Some found in the 64bit sparse array work others because users reported concrete problems they ran into. (This probably started a while ago, but when many functions were written several years back, the memory available on GPUs wasn't routinely large enough to run into these issues easily. Now it is.)

Patterns that we have used to fix these includes using delctype(...)::index_t for CArrays (this is 32bit for small arrays and 64bit for large) and others.

Agents should be able to do a decent job of finding many such issues, so let's make a sweep before 14.3, fix most of them (and if not all, create specific issues).