Make a64.release a quickcheck target

I marked all tests as slow that take more than a minute on my machine.
With this, a64.release.quickcheck takes two minutes which is about as
fast as arm.optdebug.quickcheck.

BUG=none
R=ulan@chromium.org
LOG=n

Review URL: https://codereview.chromium.org/183763008

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@19608 ce2b1a6d-e550-0410-aec6-3dcde31c8c00