Subzero: Use the memset inline threshold for memset.

Memset lowering was using the memcpy inline threshold instead of the memset threshold.

Using the memset threshold as specified (16) seems to make spec2k performance slightly worse, so change it to the original value (8).

BUG= none
R=eholk@chromium.org

Review URL: https://codereview.chromium.org/2217983003 .
3 files changed