Revert "Replace the zero handling in extend_to_full_distribution."

This reverts commit 7f56cb29787b187c8cb1b778918ca3b80184c804.

It causes uninitialized reads in the first pass setting up later cost tables.

Change-Id: I2df498df3f5c03eff359f79edf045aed0c618dc9
4 files changed