Lsan only works with x64. This broke when landing:
https://codereview.chromium.org/2085513002/

BUG=616035
TBR=jochen@chromium.org, vogelheim@chromium.org, kjellander@chromium.org
NOTRY=true
NOTREECHECKS=true

Review-Url: https://codereview.chromium.org/2086623003
Cr-Commit-Position: refs/heads/master@{#37138}