Also fix asan environment for testing on windows.

TBR=sergiyb@chromium.org

Bug: chromium:726584
Change-Id: Ic9e6afa714f4757ad1b0f2ebfa742e742e1c04b9
Reviewed-on: https://chromium-review.googlesource.com/720811
Commit-Queue: Michael Achenbach <machenbach@chromium.org>
Reviewed-by: Michael Achenbach <machenbach@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48583}