Revert "Revert "Optimize easy multiply and easy div remainder.""

This reverts commit 3654a6f50a948ead89627f398aaf86a2c2db0088.
Remove the part of the change that confused !is_div with being multiply rather
than implying remainder.

Change-Id: I202610069c69351259a320e8852543cbed4c3b3e
9 files changed