Speed up some mjsunit test cases and clean up test expectations for arm and mips.

Many skipped test cases already run very fast. Removing the corresponding expectations.

BUG=
R=jkummerow@chromium.org, mvstanton@chromium.org

Review URL: https://codereview.chromium.org/138503008

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18812 ce2b1a6d-e550-0410-aec6-3dcde31c8c00