Make sure that a continue still executed the increment part of a for
loop by adding another nested block for the body, which is the break
target for a continue in the body. The increment code lives outside
this block, in the original loop.

R=bradnelson@chromium.org
CC=mstarzinger@chromium.org

Bug: chromium:788916
Change-Id: I178b874ffac16d9237a0f4da097d2742bd93335a
Reviewed-on: https://chromium-review.googlesource.com/832447
Commit-Queue: Brad Nelson <bradnelson@chromium.org>
Reviewed-by: Brad Nelson <bradnelson@chromium.org>
Cr-Commit-Position: refs/heads/master@{#50169}