Add no-variants option to test runner.

BUG=
R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/48883003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17440 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
Fix uint32-to-smi conversion in Lithium

BUG=chromium:309623
R=vegorov@google.com, yangguo@chromium.org

Review URL: https://codereview.chromium.org/54393002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17441 ce2b1a6d-e550-0410-aec6-3dcde31c8c00