Record some notes about "innocuous" transformations
I wondered if some transformations (ticks) might be "innocuous", in the sense that they do not unlock a later transformation that does not occur in the same pass. If so, we could refrain from bumping the overall tick-count for such innocuous transformations, and perhaps terminate the simplifier one pass earlier. BUt alas I found that virtually nothing was innocuous! This commit just adds a Note to record what I learned, in case anyone wants to try again.