GN: Remove all_blink target on android builds, it does not work yet

TBR=brettw@chromium.org

Review URL: https://codereview.chromium.org/325053002

git-svn-id: svn://svn.chromium.org/blink/trunk@175920 bbb929c8-8fbe-4397-9dbb-9b2b20218538