Increase default stack size on Android with ASan to 2Mb.

BUG=263749,325685
TEST=cc_unittests on ASan/Android bot
R=glider@chromium.org, thakis@chromium.org, bulach@chromium.org, navabi@chromium.org

Review URL: https://codereview.chromium.org/136113006

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@247670 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 247670