The `FindOctave` module added by commit 170bcb6f (FindOctave: Add
module to find GNU octave, 2018-11-17, v3.14.0-rc1~283^2) has a few
problems in its implementation that need to be worked out before the
module can be included in a CMake release.  These were missed during
review.  Remove the module for now.  It can be restored later with a
fresh review.

Issue: #18991