Oilpan: Simplify ADDRESS_SANITIZER checks.

SyZyASan no longer uses ADDRESS_SANITIZER so we do not need to check
that we are not on Windows when using ADDRESS_SANITIZER.

R=oilpan-reviews@chromium.org, vegorov@chromium.org, wibling@chromium.org

Review URL: https://codereview.chromium.org/255453004

git-svn-id: svn://svn.chromium.org/blink/trunk@172498 bbb929c8-8fbe-4397-9dbb-9b2b20218538